Merge current main and reviewed GNSS into import integration

src/app/constructCatalog.js

@@ -25,6 +25,7 @@ import { createApplicationAwareness } from './layers/militaryAwareness.js';
 import { createApplicationFirms } from './layers/firms.js';
 import { createApplicationEarthquakes } from './layers/earthquakes.js';
 import { createApplicationFirePerimeters } from './layers/perimeters.js';
+import { createApplicationGnssIntegrity } from './layers/gnss.js';
 import { createApplicationCables } from './layers/submarineCables.js';
 import { createApplicationStreetLevel } from './layers/streetLevel.js';
 import { createInfrastructureLayers } from '../data/infrastructure.js';
@@ -120,6 +121,9 @@ export function createApplicationCatalog({
         createApplicationFirePerimeters({
           source: sources['fire-perimeters'],
         }),
+        createApplicationGnssIntegrity({
+          source: sources['gnss-integrity'],
+        }),
         createApplicationAlpr({ surface, source: sources.alpr }),
         createApplicationStreetLevel({
           surface,

src/app/constructCatalog.test.mjs

@@ -40,7 +40,7 @@ test('catalogs construct distinct layers and classification from their supplied
     signal: b.signal,
     surface: fixtureSurface(b.signal),
   });
-  assert.equal(first.layers.length, 30);
+  assert.equal(first.layers.length, 31);
   assert.ok(first.get('local-adsb'), 'Local ADS-B is registered');
   assert.deepEqual(
     first.metadata.find(({ id }) => id === 'local-adsb'),
@@ -60,6 +60,7 @@ test('catalogs construct distinct layers and classification from their supplied
       '2026-09-21T12:00:00.000Z',
     );
   assert.ok(first.get('fire-perimeters'));
+  assert.ok(first.get('gnss-integrity'));
   assert.ok(first.get('transit'));
   const order = first.layers.map(({ id }) => id);
   assert.deepEqual(
@@ -153,7 +154,7 @@ test('Mapillary can be omitted or replaced without changing catalog membership',
     surface: fixtureSurface(lifetime.signal),
   };
   const catalog = createApplicationCatalog(options);
-  assert.equal(catalog.layers.length, 30);
+  assert.equal(catalog.layers.length, 31);
   assert.deepEqual(catalog.get('street-level').providerIds, []);
   assert.equal(
     catalogControlServices(catalog).streetLevelLayer,

src/app/layers/gnss.js

@@ -0,0 +1,6 @@
+import { createGnssIntegrityLayer } from '../../layers/gnss/index.js';
+
+/** Wire the adsb.lol GNSS navigation-integrity layer into the application catalog. */
+export function createApplicationGnssIntegrity(options) {
+  return createGnssIntegrityLayer(options);
+}

src/app/sourceComposition.js

@@ -46,6 +46,7 @@ export const CATALOG_SOURCE_CONTRACTS = Object.freeze({
   cyclones: contract(['weather-cyclones'], ['getSnapshot']),
   earthquakes: contract(['earthquakes'], ['getSnapshot']),
   'fire-perimeters': contract(['fire-perimeters'], ['getSnapshot']),
+  'gnss-integrity': contract(['gnss-integrity'], ['getSnapshot']),
   cables: contract(['telegeography-submarine-cables'], ['fetch']),
   transit: contract(['transit'], ['requestSnapshot', 'getHistory']),
 });

src/app/sourceComposition.test.mjs

@@ -37,7 +37,7 @@ test('every acquisition source can be omitted without losing catalog membership'
 
 test('all acquisition sources may be absent, and enable fails before initializing or fetching', async (t) => {
   const actual = catalog({}, t);
-  assert.equal(actual.layers.length, 30);
+  assert.equal(actual.layers.length, 31);
   const manager = new LayerLifecycle(
     {},
     { getSourceAvailability: actual.getSourceAvailability },

src/cockpitMath.js

@@ -83,6 +83,26 @@ export function cockpitAltitudeDisplayFt(altitudeM, onGround) {
   return Number.isFinite(altitudeM) ? altitudeM * 3.28084 : null;
 }
 
+/**
+ * HUD wording for a tracked aircraft's transponder emergency, or null.
+ * States what was broadcast, never a conclusion about the flight: the Mode A
+ * code when it names the status, else the ADS-B field it came from (an
+ * unrelated squawk is dropped).
+ * @param {{label?: string, squawk?: string|null, source?: string,
+ *   severity?: string}|null|undefined} emergency
+ * @returns {string|null}
+ */
+export function formatCockpitEmergency(emergency) {
+  const label = String(emergency?.label || '')
+    .trim()
+    .toUpperCase();
+  if (!label) return null;
+  if (emergency.source === 'squawk' && emergency.squawk)
+    return `SQUAWK ${emergency.squawk} · ${label}`;
+  const field = emergency.severity === 'priority' ? 'PRIORITY' : 'EMERGENCY';
+  return `ADS-B ${field} · ${label}`;
+}
+
 /** Format the cockpit Context scope without overstating installation coverage. */
 export function formatCockpitContextScope(
   subjectLabel,

src/cockpitMath.test.mjs

@@ -13,6 +13,7 @@ import {
   compassDivisions,
   formatAltitudeRulerTick,
   formatCockpitContextScope,
+  formatCockpitEmergency,
   formatCompassDivision,
   formatSpeedRulerTick,
   normalizeHeading,
@@ -364,3 +365,21 @@ test('tracked-identity resolution falls back to layer precedence', () => {
   assert.equal(resolveTrackedAircraftInfo({ trackedId: 'flights:aaa077' }), null);
   assert.equal(resolveTrackedAircraftInfo(), null);
 });
+
+test('cockpit emergency wording states the broadcast code, not a conclusion', () => {
+  assert.equal(
+    formatCockpitEmergency({ label: 'General emergency', squawk: '7700', source: 'squawk', severity: 'emergency' }),
+    'SQUAWK 7700 · GENERAL EMERGENCY',
+  );
+  assert.equal(
+    formatCockpitEmergency({ label: 'Downed aircraft', squawk: '1200', source: 'ads-b', severity: 'emergency' }),
+    'ADS-B EMERGENCY · DOWNED AIRCRAFT',
+    'an unrelated squawk is not quoted beside an ADS-B status',
+  );
+  assert.equal(
+    formatCockpitEmergency({ label: 'Minimum fuel', squawk: null, source: 'ads-b', severity: 'priority' }),
+    'ADS-B PRIORITY · MINIMUM FUEL',
+  );
+  assert.equal(formatCockpitEmergency(null), null);
+  assert.equal(formatCockpitEmergency({ label: '' }), null);
+});

src/data/adsbLolFallback.js

@@ -43,11 +43,18 @@ export function normalizeAdsbLolAircraftState(aircraft, nowSeconds) {
     .toLowerCase();
   const latitude = finiteNumber(aircraft?.lat);
   const longitude = finiteNumber(aircraft?.lon);
-  if (!hex || latitude === null || longitude === null) return null;
+  if (
+    !hex ||
+    latitude === null ||
+    longitude === null ||
+    Math.abs(latitude) > 90 ||
+    Math.abs(longitude) > 180
+  )
+    return null;
 
   const seenPosition = Math.max(
     0,
-    finiteNumber(aircraft?.seen_pos) ?? finiteNumber(aircraft?.seen) ?? 0,
+    finiteNumber(aircraft?.seen_pos) ?? finiteNumber(aircraft?.seen) ?? NaN,
   );
   const seen = Math.max(0, finiteNumber(aircraft?.seen) ?? seenPosition);
   const onGround = aircraft?.alt_baro === 'ground';
@@ -62,8 +69,10 @@ export function normalizeAdsbLolAircraftState(aircraft, nowSeconds) {
     hex,
     String(aircraft?.flight || aircraft?.r || '').trim() || null,
     null,
-    Math.max(0, nowSeconds - seenPosition),
-    Math.max(0, nowSeconds - seen),
+    Number.isFinite(seenPosition)
+      ? Math.max(0, nowSeconds - seenPosition)
+      : null,
+    Number.isFinite(seen) ? Math.max(0, nowSeconds - seen) : null,
     longitude,
     latitude,
     barometricFeet === null ? null : barometricFeet * FOOT_TO_M,
@@ -94,8 +103,28 @@ export function normalizeAdsbLolPointResponse(payload) {
       : Math.floor(
           responseNow > 10_000_000_000 ? responseNow / 1000 : responseNow,
         );
-  const states = (Array.isArray(payload?.ac) ? payload.ac : [])
-    .map((aircraft) => normalizeAdsbLolAircraftState(aircraft, nowSeconds))
-    .filter(Boolean);
-  return { time: nowSeconds, states };
+  const aircraft = Array.isArray(payload?.ac) ? payload.ac : [];
+  const states = [];
+  // Keep the OpenSky vectors unchanged. The regional fallback's extra readsb
+  // status travels alongside them, keyed only to admitted aircraft.
+  const admitted = new Set();
+  const statuses = [];
+  for (const row of aircraft) {
+    const state = normalizeAdsbLolAircraftState(row, nowSeconds);
+    if (!state) continue;
+    states.push(state);
+    // The live contract admits the first valid vector for each ICAO. Its
+    // status must come from that same row, never an invalid or later duplicate.
+    const id = state[0];
+    if (admitted.has(id)) continue;
+    admitted.add(id);
+    if (typeof row.emergency === 'string')
+      statuses.push([id, row.emergency.trim().toLowerCase()]);
+  }
+  const emergencyByIcao = Object.fromEntries(statuses);
+  return {
+    time: nowSeconds,
+    states,
+    ...(Object.keys(emergencyByIcao).length ? { emergencyByIcao } : {}),
+  };
 }

src/data/aircraftEmergency.js

@@ -0,0 +1,93 @@
+/**
+ * Transponder emergency status for one aircraft, from the Mode A squawk and
+ * the ADS-B emergency/priority field.
+ *
+ * Emergency squawks are ICAO-standard worldwide: 7500 unlawful interference,
+ * 7600 radio failure, 7700 general emergency. readsb (adsb.lol) also reports
+ * `emergency`, "a superset of the 7x00 squawks": none, general, lifeguard,
+ * minfuel, nordo, unlawful, downed, reserved. OpenSky state vectors carry the
+ * squawk only.
+ *
+ * The status is what the transponder broadcast in THIS poll, never a finding:
+ * crews pass through 7x00 codes while dialling. Highlighting follows the latest
+ * broadcast, which does not confirm an incident or its resolution.
+ */
+
+/** @constant {string} Tint for aircraft broadcasting an emergency (not a priority). */
+export const EMERGENCY_TINT_CSS = '#FF4444';
+
+const SQUAWK_KINDS = { 7500: 'unlawful', 7600: 'nordo', 7700: 'general' };
+
+const KINDS = {
+  general: { label: 'General emergency', severity: 'emergency' },
+  unlawful: { label: 'Unlawful interference', severity: 'emergency' },
+  nordo: { label: 'Radio failure', severity: 'emergency' },
+  downed: { label: 'Downed aircraft', severity: 'emergency' },
+  minfuel: { label: 'Minimum fuel', severity: 'priority' },
+  lifeguard: { label: 'Lifeguard (medical priority)', severity: 'priority' },
+};
+
+/**
+ * A Mode A code as its four octal digits, else null.
+ * @param {unknown} value
+ * @returns {string|null}
+ */
+export function normalizeSquawk(value) {
+  const code = String(value ?? '').trim();
+  return /^[0-7]{4}$/.test(code) ? code : null;
+}
+
+/**
+ * Emergency status from one observation. Higher severity wins; an ADS-B
+ * emergency wins a tie. A
+ * 7x00 squawk counts even when the ADS-B field says `none`.
+ * @param {{squawk?: unknown, emergency?: unknown}} [observation]
+ * @returns {{kind: string, label: string, severity: 'emergency'|'priority',
+ *   squawk: string|null, source: 'ads-b'|'squawk'}|null} `source` is
+ *   'squawk' when the Mode A code itself names the status (so it can be
+ *   quoted), else 'ads-b'.
+ */
+export function aircraftEmergency({ squawk, emergency } = {}) {
+  const code = normalizeSquawk(squawk);
+  const reported = String(emergency ?? '')
+    .trim()
+    .toLowerCase();
+  const fromAdsb = Object.hasOwn(KINDS, reported);
+  const squawkKind = SQUAWK_KINDS[code] ?? null;
+  const kind =
+    fromAdsb && (KINDS[reported].severity === 'emergency' || !squawkKind)
+      ? reported
+      : squawkKind;
+  if (!kind) return null;
+  return {
+    kind,
+    ...KINDS[kind],
+    squawk: code,
+    source: SQUAWK_KINDS[code] === kind ? 'squawk' : 'ads-b',
+  };
+}
+
+/**
+ * How a summary may phrase the status without flattening it into an incident:
+ * quote the code when the Mode A squawk itself names the status, otherwise
+ * attribute it to the ADS-B emergency field.
+ * @param {{kind?: string, squawk?: string|null, source?: string}|null|undefined} status
+ * @returns {string|null} e.g. 'broadcasting squawk 7700 (general emergency)'
+ *   or 'ADS-B reports general emergency'; null when there is no status.
+ */
+export function emergencyBroadcastPhrase(status) {
+  if (!status || !Object.hasOwn(KINDS, status.kind)) return null;
+  const label = KINDS[status.kind].label.toLowerCase();
+  return status.source === 'squawk' && status.squawk
+    ? `broadcasting squawk ${status.squawk} (${label})`
+    : `ADS-B reports ${label}`;
+}
+
+/**
+ * True when the aircraft is broadcasting an emergency (not a priority status).
+ * @param {{severity?: string}|null|undefined} status
+ * @returns {boolean}
+ */
+export function isEmergency(status) {
+  return status?.severity === 'emergency';
+}

src/data/aircraftEmergency.test.mjs

@@ -0,0 +1,95 @@
+// src/data/aircraftEmergency.test.mjs
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  aircraftEmergency,
+  emergencyBroadcastPhrase,
+  isEmergency,
+  normalizeSquawk,
+} from './aircraftEmergency.js';
+
+test('the three ICAO emergency squawks map to their kinds', () => {
+  assert.equal(aircraftEmergency({ squawk: '7500' }).kind, 'unlawful');
+  assert.equal(aircraftEmergency({ squawk: '7600' }).kind, 'nordo');
+  const general = aircraftEmergency({ squawk: ' 7700 ' });
+  assert.deepEqual(general, {
+    kind: 'general',
+    label: 'General emergency',
+    severity: 'emergency',
+    squawk: '7700',
+    source: 'squawk',
+  });
+});
+
+test('ordinary codes, blanks and non-octal values are not emergencies', () => {
+  for (const squawk of ['1200', '7000', '2000', '', null, undefined, '7800'])
+    assert.equal(aircraftEmergency({ squawk }), null, String(squawk));
+  assert.equal(aircraftEmergency(), null);
+  assert.equal(normalizeSquawk('7800'), null);
+  assert.equal(normalizeSquawk(7700), '7700');
+  assert.equal(normalizeSquawk('770'), null);
+});
+
+test('the ADS-B emergency field wins, and `none` defers to the squawk', () => {
+  const minfuel = aircraftEmergency({ squawk: '4521', emergency: 'MinFuel' });
+  assert.equal(minfuel.kind, 'minfuel');
+  assert.equal(minfuel.severity, 'priority');
+  assert.equal(minfuel.source, 'ads-b');
+  assert.equal(minfuel.squawk, '4521');
+  assert.equal(
+    aircraftEmergency({ squawk: '7700', emergency: 'none' }).source,
+    'squawk',
+  );
+  assert.equal(
+    aircraftEmergency({ squawk: '7700', emergency: 'general' }).source,
+    'squawk',
+    'a code that names the status stays quotable',
+  );
+  assert.equal(
+    aircraftEmergency({ squawk: '1200', emergency: 'general' }).source,
+    'ads-b',
+  );
+  assert.equal(aircraftEmergency({ emergency: 'downed' }).kind, 'downed');
+  assert.equal(aircraftEmergency({ emergency: 'none' }), null);
+  assert.equal(aircraftEmergency({ emergency: 'reserved' }), null);
+});
+
+test('priority statuses are reported but are not emergencies', () => {
+  assert.equal(isEmergency(aircraftEmergency({ squawk: '7700' })), true);
+  assert.equal(
+    isEmergency(aircraftEmergency({ emergency: 'lifeguard' })),
+    false,
+  );
+  assert.equal(isEmergency(aircraftEmergency({ emergency: 'minfuel' })), false);
+  assert.equal(isEmergency(null), false);
+});
+
+test('the broadcast phrase quotes a naming code, else attributes ADS-B', () => {
+  assert.equal(
+    emergencyBroadcastPhrase(aircraftEmergency({ squawk: '7700' })),
+    'broadcasting squawk 7700 (general emergency)',
+  );
+  assert.equal(
+    emergencyBroadcastPhrase(
+      aircraftEmergency({ squawk: '1200', emergency: 'general' }),
+    ),
+    'ADS-B reports general emergency',
+  );
+  assert.equal(
+    emergencyBroadcastPhrase(aircraftEmergency({ emergency: 'lifeguard' })),
+    'ADS-B reports lifeguard (medical priority)',
+  );
+  assert.equal(emergencyBroadcastPhrase(null), null);
+  assert.equal(emergencyBroadcastPhrase({ kind: 'reserved' }), null);
+});
+
+test('an emergency squawk outranks an ADS-B priority', () => {
+  assert.equal(
+    aircraftEmergency({ squawk: '7700', emergency: 'lifeguard' }).kind,
+    'general',
+  );
+  assert.equal(
+    aircraftEmergency({ squawk: '7500', emergency: 'minfuel' }).kind,
+    'unlawful',
+  );
+});

src/data/aircraftEmergencyAnalyst.test.mjs

@@ -0,0 +1,524 @@
+import * as Cesium from 'cesium';
+import { TRACKED_ICON_COLOR } from '../layers/military/policy.js';
+import { createRendering as civilRendering } from '../layers/flights/rendering.js';
+import { createRendering as militaryRendering } from '../layers/military/rendering.js';
+import { createMilitarySnapshotRenderer } from '../layers/military/snapshotRenderer.js';
+import { aircraftEmergency } from './aircraftEmergency.js';
+// Source-to-voice provenance, status retention/clearing, contact-time contracts,
+// and civil/military billboard, Cockpit and model tint regressions.
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { openSkySnapshot, readsbSnapshot } from '../sources/live/index.js';
+import { FlightRecords } from '../layers/flights/records.js';
+import { MilitaryFlightRecords } from '../layers/military/records.js';
+import { mapAnalystRecord as mapFlight } from './flights.js';
+import { mapAnalystRecord as mapMilitary } from './militaryFlights.js';
+import { createAnalystEngine } from './analystEngine.js';
+import { normalizeAdsbLolPointResponse } from './adsbLolFallback.js';
+import { createGevActionRunner } from '../voice/gevActions.js';
+
+const NOW_MS = 1800000000000;
+
+test('fallback status belongs to the first valid admitted aircraft row', () => {
+  const valid = { hex: 'a1b2c3', lat: 30, lon: -97, squawk: '1200' };
+  for (const status of [undefined, 'general', 'none']) {
+    const payload = normalizeAdsbLolPointResponse({
+      now: NOW_MS,
+      ac: [
+        { ...valid, lat: 100, emergency: 'general' },
+        { ...valid, emergency: status },
+        { ...valid, lat: null, emergency: 'general' },
+        { ...valid, emergency: status === 'general' ? 'none' : 'general' },
+      ],
+    });
+    const snapshot = openSkySnapshot(payload, { now: NOW_MS });
+    assert.equal(snapshot.records.length, 1);
+    assert.equal(snapshot.records[0].emergency, status);
+    assert.equal(snapshot.records[0].latitude, 30);
+  }
+});
+
+function civilStore() {
+  return new FlightRecords({
+    geoidHeight: () => 0,
+    cachedGroundFloor: () => null,
+    floorAltitudeM: (value) => value,
+    approxDistanceKm: () => 0,
+  });
+}
+const receiveContext = {
+  viewerLatDeg: null,
+  viewerLonDeg: null,
+  trackedId: null,
+  floorWarmPoints: [],
+};
+
+test('real civil fallback preserves ADS-B emergency and priority, then clears', () => {
+  const store = civilStore();
+  const aircraft = {
+    hex: 'a1b2c3',
+    flight: 'TEST1',
+    lat: 30,
+    lon: -97,
+    alt_baro: 10000,
+    gs: 150,
+    track: 90,
+    squawk: '1200',
+    seen: 3,
+    seen_pos: 1,
+  };
+  for (const [status, expectedKind, flagged] of [
+    ['general', 'general', true],
+    ['minfuel', 'minfuel', false],
+    ['none', null, false],
+  ]) {
+    const payload = normalizeAdsbLolPointResponse({
+      now: NOW_MS,
+      ac: [{ ...aircraft, emergency: status }],
+    });
+    assert.equal(
+      payload.states[0].length,
+      18,
+      'fallback vectors retain the OpenSky shape',
+    );
+    const [observation] = openSkySnapshot(payload, { now: NOW_MS }).records;
+    const result = mapFlight(
+      aircraft.hex,
+      store.receive(observation, receiveContext).meta,
+    );
+    assert.equal(result.emergency, flagged);
+    assert.equal(result.emergencyKind, expectedKind);
+    assert.equal(result.emergencySource, expectedKind ? 'ads-b' : null);
+    assert.equal(result.lastContactAtMs, NOW_MS - 3000);
+  }
+});
+
+test('changed status without contact time retains general contact, including voice projection', async () => {
+  const store = civilStore();
+  const [observation] = readsbSnapshot(
+    {
+      ac: [
+        {
+          hex: 'a1b2c3',
+          flight: 'TEST1',
+          lat: 30,
+          lon: -97,
+          alt_baro: 10000,
+          gs: 150,
+          track: 90,
+          squawk: '1200',
+          emergency: 'general',
+          seen: 3,
+          seen_pos: 1,
+        },
+      ],
+    },
+    { observedAtMs: NOW_MS, now: NOW_MS },
+  ).records;
+  store.receive(observation, receiveContext);
+  const meta = store.receive(
+    { ...observation, contactTimeMs: null, squawk: '7600', emergency: 'none' },
+    receiveContext,
+  ).meta;
+  const record = mapFlight(observation.id, meta);
+  assert.equal(record.emergencyKind, 'nordo');
+  assert.equal(record.lastContactAtMs, NOW_MS - 3000);
+  assert.equal(Object.hasOwn(record, 'observedAtMs'), false);
+  globalThis.window = globalThis.window || {
+    clearTimeout,
+    setTimeout,
+    requestIdleCallback: null,
+  };
+  const flights = {
+    id: 'flights',
+    source: 'fixture',
+    getStats: () => ({ count: 1 }),
+    getAnalystRecords: () => [record],
+  };
+  const runner = createGevActionRunner({
+    viewer: {
+      clock: { onTick: { addEventListener: () => () => {} } },
+      scene: { canvas: { addEventListener() {}, removeEventListener() {} } },
+      camera: {
+        moveEnd: { addEventListener() {} },
+        positionCartographic: {
+          height: 300000,
+          latitude: 0.52,
+          longitude: -1.71,
+        },
+      },
+    },
+    styleManager: {
+      getContextModeState: () => ({ mode: null, active: false }),
+      getCockpitState: () => ({ active: false }),
+    },
+    dataManager: {
+      layers: new Map([['flights', { module: flights }]]),
+      isEnabled: (id) => id === 'flights',
+      getAll: () => [
+        { id: 'flights', name: 'Flights', enabled: true, stats: { count: 1 } },
+      ],
+    },
+  });
+  try {
+    const result = await runner('analyst_query', {
+      layers: ['flights'],
+      scope: { kind: 'anywhere' },
+      filters: [{ field: 'emergency', op: 'eq', value: true }],
+    });
+    assert.equal(result.ok, true);
+    assert.equal(result.items[0].emergency, true);
+    assert.equal(result.items[0].lastContactAtMs, NOW_MS - 3000);
+    assert.equal(result.items[0].emergencySource, 'squawk');
+    assert.equal(
+      result.items[0].emergencyBroadcast,
+      'broadcasting squawk 7600 (radio failure)',
+    );
+    assert.equal(
+      Object.hasOwn(result.items[0], 'time'),
+      false,
+      'general contact is not a generic incident timestamp',
+    );
+  } finally {
+    runner.dispose?.();
+  }
+});
+
+// OpenSky /states/all: [icao24, callsign, origin_country, time_position,
+// last_contact, lon, lat, baro_alt, on_ground, velocity, true_track,
+// vertical_rate, sensors, geo_alt, squawk, spi, position_source, category].
+const OPENSKY = {
+  time: NOW_MS / 1000,
+  states: [
+    [
+      'a1b2c3',
+      'SWA696  ',
+      'United States',
+      NOW_MS / 1000 - 6,
+      NOW_MS / 1000 - 3,
+      -97.67,
+      30.19,
+      3000,
+      false,
+      150,
+      180,
+      -5,
+      null,
+      3040,
+      '7700',
+      false,
+      0,
+      4,
+    ],
+  ],
+};
+
+// adsb.lol /v2/mil: readsb aircraft with `seen`/`seen_pos` ages in seconds.
+const ADSB_LOL = {
+  ac: [
+    {
+      hex: 'ae01ce',
+      flight: 'RCH123  ',
+      t: 'C17',
+      lat: 31.1,
+      lon: -97.4,
+      alt_baro: 18000,
+      gs: 300,
+      track: 90,
+      squawk: '1200',
+      emergency: 'general',
+      seen: 1.5,
+      seen_pos: 2,
+    },
+  ],
+};
+
+function civilAnalystRecord() {
+  const [row] = openSkySnapshot(OPENSKY, { now: NOW_MS }).records;
+  const store = new FlightRecords({
+    geoidHeight: () => 0,
+    cachedGroundFloor: () => null,
+    floorAltitudeM: (altitude) => altitude,
+    approxDistanceKm: () => 0,
+  });
+  const { meta } = store.receive(row, {
+    viewerLatDeg: null,
+    viewerLonDeg: null,
+    trackedId: null,
+    floorWarmPoints: [],
+  });
+  return mapFlight(row.id, meta);
+}
+
+function militaryAnalystRecord() {
+  const [row] = readsbSnapshot(ADSB_LOL, {
+    observedAtMs: NOW_MS,
+    now: NOW_MS,
+  }).records;
+  const store = new MilitaryFlightRecords({
+    geoidHeight: () => 0,
+    cachedGroundFloor: () => null,
+    floorAltitudeM: (altitude) => altitude,
+  });
+  const { meta } = store.receive(row, {
+    observedAtMs: NOW_MS,
+    floorWarmPoints: [],
+    modelOwnsVisual: false,
+  });
+  return mapMilitary(row.id, meta);
+}
+
+test('OpenSky 7700 and adsb.lol emergency=general differ only in provenance', () => {
+  const civil = civilAnalystRecord();
+  const military = militaryAnalystRecord();
+
+  assert.equal(civil.emergency, true);
+  assert.equal(civil.emergencyKind, 'general');
+  assert.equal(civil.squawk, '7700');
+  assert.equal(civil.emergencySource, 'squawk');
+  assert.equal(
+    civil.emergencyBroadcast,
+    'broadcasting squawk 7700 (general emergency)',
+  );
+  assert.equal(civil.lastContactAtMs, NOW_MS - 3000, 'OpenSky last_contact');
+
+  assert.equal(military.emergency, true);
+  assert.equal(military.emergencyKind, 'general');
+  assert.equal(military.squawk, '1200', 'the code is not an emergency code');
+  assert.equal(military.emergencySource, 'ads-b');
+  assert.equal(military.emergencyBroadcast, 'ADS-B reports general emergency');
+  assert.equal(military.lastContactAtMs, NOW_MS - 1500, 'snapshot time - seen');
+});
+
+test('the analyst can filter emergencies by source', async () => {
+  const records = {
+    flights: [civilAnalystRecord()],
+    military: [militaryAnalystRecord()],
+  };
+  const engine = createAnalystEngine({
+    getRecords: (key) => records[key] || [],
+    resolveRegionRing: async () => null,
+    getViewContext: () => ({ lat: 30.5, lon: -97.5, viewRadiusKm: 500 }),
+  });
+  const query = (value) =>
+    engine.query({
+      layers: ['flights', 'military'],
+      scope: { kind: 'anywhere' },
+      filters: [
+        { field: 'emergency', op: 'eq', value: true },
+        { field: 'emergencySource', op: 'eq', value },
+      ],
+    });
+  const bySquawk = await query('squawk');
+  assert.deepEqual(
+    bySquawk.items.map((item) => [item.icao24, item.emergencyBroadcast]),
+    [['a1b2c3', 'broadcasting squawk 7700 (general emergency)']],
+  );
+  const byAdsb = await query('ads-b');
+  assert.deepEqual(
+    byAdsb.items.map((item) => [item.icao24, item.emergencyBroadcast]),
+    [['ae01ce', 'ADS-B reports general emergency']],
+  );
+});
+
+test('military status changes retain only the latest known general contact', () => {
+  const store = new MilitaryFlightRecords({
+    geoidHeight: () => 0,
+    cachedGroundFloor: () => null,
+    floorAltitudeM: (v) => v,
+  });
+  const [observation] = readsbSnapshot(ADSB_LOL, {
+    observedAtMs: NOW_MS,
+    now: NOW_MS,
+  }).records;
+  const context = {
+    observedAtMs: NOW_MS,
+    floorWarmPoints: [],
+    modelOwnsVisual: false,
+  };
+  const unknown = mapMilitary(
+    observation.id,
+    store.receive({ ...observation, contactTimeMs: null }, context).meta,
+  );
+  assert.equal(unknown.lastContactAtMs, null);
+  store.receive(observation, context);
+  const changed = mapMilitary(
+    observation.id,
+    store.receive(
+      {
+        ...observation,
+        contactTimeMs: null,
+        squawk: '7600',
+        emergency: 'none',
+      },
+      context,
+    ).meta,
+  );
+  assert.equal(changed.emergencyKind, 'nordo');
+  assert.equal(changed.lastContactAtMs, NOW_MS - 1500);
+});
+
+test('fallback missing contact age retains known contact through the real converter', () => {
+  const store = civilStore();
+  const row = {
+    hex: 'a1b2c3',
+    lat: 30,
+    lon: -97,
+    squawk: '1200',
+    emergency: 'general',
+    seen: 3,
+    seen_pos: 1,
+  };
+  const receive = (row) =>
+    store.receive(
+      openSkySnapshot(
+        normalizeAdsbLolPointResponse({ now: NOW_MS, ac: [row] }),
+        { now: NOW_MS },
+      ).records[0],
+      receiveContext,
+    ).meta;
+  const first = receive(row);
+  const second = receive({ ...row, seen: undefined, seen_pos: undefined });
+  assert.equal(second.lastContactEpochMs, first.lastContactEpochMs);
+});
+
+test('one omitted ADS-B status poll is retained; explicit none and changed squawk clear immediately', () => {
+  const store = civilStore();
+  const row = {
+    hex: 'a1b2c3',
+    lat: 30,
+    lon: -97,
+    squawk: '1200',
+    emergency: 'general',
+    seen: 3,
+  };
+  const receive = (row) =>
+    store.receive(
+      openSkySnapshot(
+        normalizeAdsbLolPointResponse({ now: NOW_MS, ac: [row] }),
+        { now: NOW_MS },
+      ).records[0],
+      receiveContext,
+    ).meta;
+  assert.equal(receive(row).emergency.kind, 'general');
+  assert.equal(
+    receive({ ...row, emergency: undefined }).emergency?.kind,
+    'general',
+  );
+  assert.equal(receive({ ...row, emergency: undefined }).emergency, null);
+  receive(row);
+  assert.equal(receive({ ...row, emergency: 'none' }).emergency, null);
+  receive(row);
+  assert.equal(
+    receive({ ...row, emergency: undefined, squawk: '2000' }).emergency,
+    null,
+  );
+});
+
+function renderHarness(factory) {
+  const flightState = { records: { data: new Map() }, _trackedIcao: null };
+  const rendering = factory({
+    flightState,
+    services: {
+      militaryRegistry: { isMilitaryIcao: (id) => id === 'mil' },
+      aircraftPresentation: {},
+      camera: {},
+      focus: {},
+      recession: {},
+    },
+    parts: {},
+  });
+  return { flightState, rendering };
+}
+
+test('tint priorities cover normal, priority, emergency, tracking and Cockpit dots', () => {
+  for (const factory of [civilRendering, militaryRendering]) {
+    const { flightState, rendering } = renderHarness(factory);
+    const normal = rendering._fleetBillboardColor('civil', {});
+    assert.equal(
+      rendering._fleetBillboardColor('civil', {
+        emergency: aircraftEmergency({ emergency: 'minfuel' }),
+      }),
+      normal,
+    );
+    const red = rendering._fleetBillboardColor('civil', {
+      emergency: aircraftEmergency({ squawk: '7700' }),
+    });
+    assert.ok(red.red > 0.9 && red.green < 0.5);
+    flightState.records.data.set('civil', {
+      emergency: aircraftEmergency({ squawk: '7700' }),
+    });
+    assert.equal(rendering._modelColor('civil'), red);
+    if (rendering._cockpitContactColor)
+      assert.equal(rendering._cockpitContactColor('civil'), red);
+    flightState._trackedIcao = 'civil';
+    assert.equal(
+      rendering._modelColor('civil'),
+      factory === civilRendering ? Cesium.Color.CYAN : TRACKED_ICON_COLOR,
+    );
+    flightState._trackedIcao = null;
+    flightState.records.data.set('civil', { emergency: null });
+    assert.equal(rendering._modelColor('civil'), normal);
+  }
+});
+
+test('GERMAN: an existing untracked military billboard repaints each poll without alpha loss', () => {
+  const { flightState, rendering } = renderHarness(militaryRendering);
+  const bb = {
+    color: rendering._fleetBillboardColor('abc123').withAlpha(0.65),
+  };
+  Object.assign(flightState, {
+    _billboards: new Map([['abc123', bb]]),
+    _models: new Map(),
+    _positionHistory: new Map(),
+    _cullPositions: new Map(),
+    _groundSnap: { forget() {} },
+    _cockpitContactMode: false,
+  });
+  const records = new MilitaryFlightRecords({
+    geoidHeight: () => 0,
+    cachedGroundFloor: () => null,
+    floorAltitudeM: (value) => value,
+  });
+  flightState.records = records;
+  const apply = createMilitarySnapshotRenderer({
+    flightState,
+    records,
+    groundFloor: { warmGroundFloor() {}, cachedGroundFloor: () => null },
+    meshFloor: { sampleMeshFloorCells() {} },
+    militaryRegistry: { registerMilitaryIcaos() {} },
+    rendering: {
+      ...rendering,
+      _syncModelToClass() {},
+      _applyFleetBillboardPresentation() {},
+    },
+    motion: {},
+    tracking: {},
+    queries: {},
+  });
+  for (const [emergency, red] of [
+    ['general', true],
+    ['none', false],
+    ['general', true],
+  ]) {
+    const snapshot = readsbSnapshot(
+      {
+        ac: [
+          {
+            hex: 'abc123',
+            lat: 30,
+            lon: -97,
+            alt_baro: 10000,
+            squawk: '1200',
+            emergency,
+            seen_pos: 1,
+          },
+        ],
+      },
+      { observedAtMs: NOW_MS },
+    );
+    apply(snapshot, {});
+    assert.equal(bb.color.green < 0.5, red);
+    assert.equal(bb.color.alpha, 0.65);
+  }
+});

src/data/aircraftRecession.js

@@ -242,7 +242,7 @@ export function applyAircraftBillboardTreatment({
 }
 
 /**
- * Apply the already-composed aircraft alpha to an ambient glTF model without
+ * Apply layer-owned hue and composed aircraft alpha to an ambient glTF model without
  * disturbing Cesium's existing MIX/colorBlendAmount presentation semantics.
  * @param {object} input
  * @param {object} input.model
@@ -261,7 +261,10 @@ export function applyAircraftModelTreatment({
   if (!model || !baseColor || !Number.isFinite(alpha)) return 0;
   if (
     Number.isFinite(model.color?.alpha) &&
-    Math.abs(model.color.alpha - alpha) <= tuning.writeEpsilon
+    Math.abs(model.color.alpha - alpha) <= tuning.writeEpsilon &&
+    model.color.red === baseColor.red &&
+    model.color.green === baseColor.green &&
+    model.color.blue === baseColor.blue
   )
     return 0;
   model.color = baseColor.withAlpha(alpha);

src/data/aircraftRecession.test.mjs

@@ -142,3 +142,15 @@ test('ambient model presentation receives composed alpha without changing blend
   assert.equal(model.colorBlendAmount, 0.9);
   assert.equal(applyAircraftModelTreatment({ model, baseColor: color, alpha: 0.2, params }), 0);
 });
+
+
+test('model hue changes at constant alpha, then clears without redundant writes', () => {
+  const color = (red,green,blue) => ({red,green,blue,withAlpha(alpha){return {red,green,blue,alpha};}});
+  const model = {color:color(1,1,1).withAlpha(0.65)};
+  assert.equal(applyAircraftModelTreatment({model,baseColor:color(1,0.2,0.2),alpha:0.65}),1);
+  assert.equal(model.color.green,0.2);
+  assert.equal(model.color.alpha,0.65);
+  assert.equal(applyAircraftModelTreatment({model,baseColor:color(1,0.2,0.2),alpha:0.65}),0);
+  assert.equal(applyAircraftModelTreatment({model,baseColor:color(1,1,1),alpha:0.65}),1);
+  assert.equal(model.color.green,1);
+});

src/data/dataCredits.js

@@ -111,7 +111,7 @@ export const DATA_CREDITS = [
   {
     key: 'adsblol',
     html:
-      'Military flights, aircraft traces & bounded regional flight fallback: ' +
+      'Military flights, aircraft traces, bounded regional flight fallback & GNSS navigation integrity: ' +
       '<a href="https://adsb.lol" target="_blank" rel="noopener">adsb.lol</a> ' +
       '(ODbL 1.0)',
   },

src/data/firms-coordinate-evidence.test.mjs

@@ -0,0 +1,69 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { parseFirmsCsv } from './firmsCsv.js';
+import { adaptFirmsRecords } from './firmsAdapt.js';
+test('missing positions do not become fire detections at zero coordinates', () => {
+  const csv =
+    'latitude,longitude,acq_date,acq_time,confidence,frp\n,1,2026-07-16,1200,n,1\n1, ,2026-07-16,1200,n,1\n95,1,2026-07-16,1200,n,1\n1,181,2026-07-16,1200,n,1\n0,0,2026-07-16,1200,n,1\n-90,-180,2026-07-16,1200,n,1';
+  assert.deepEqual(
+    parseFirmsCsv(csv).map((r) => [r.lat, r.lon]),
+    [
+      [0, 0],
+      [-90, -180],
+    ],
+  );
+  const records = [
+    { lat: null, lon: 1 },
+    { lat: '', lon: 1 },
+    { lat: false, lon: 1 },
+    { lat: 95, lon: 1 },
+    { lat: 1, lon: 181 },
+    { lat: '0', lon: 0 },
+    { lat: -90, lon: -180 },
+  ];
+  assert.deepEqual(
+    adaptFirmsRecords(records).map((r) => [r.index, r.lat, r.lon]),
+    [
+      [0, 0, 0],
+      [1, -90, -180],
+    ],
+  );
+});
+
+test('both axes keep their exact bounds and drop values just past them', () => {
+  const row = (lat, lon) => `${lat},${lon},2026-07-16,1200,n,1`;
+  const csv = [
+    'latitude,longitude,acq_date,acq_time,confidence,frp',
+    row(90, 180),
+    row(-90, -180),
+    row(90.000001, 0),
+    row(-90.000001, 0),
+    row(0, 180.000001),
+    row(0, -180.000001),
+    row(' ', 5),
+    row(5, '\t'),
+  ].join('\n');
+  assert.deepEqual(
+    parseFirmsCsv(csv).map((r) => [r.lat, r.lon]),
+    [
+      [90, 180],
+      [-90, -180],
+    ],
+  );
+  const kept = adaptFirmsRecords([
+    { lat: 90, lon: 180 },
+    { lat: '-90', lon: '-180' },
+    { lat: -90.000001, lon: 0 },
+    { lat: 0, lon: -180.000001 },
+    { lat: 5, lon: ' ' },
+    { lat: 5, lon: undefined },
+    { lat: [5], lon: 5 },
+  ]);
+  assert.deepEqual(
+    kept.map((r) => [r.lat, r.lon]),
+    [
+      [90, 180],
+      [-90, -180],
+    ],
+  );
+});

src/data/firmsAdapt.js

@@ -7,8 +7,8 @@
  */
 
 /**
- * Map proxy fire records into internal fire records. Records with
- * non-finite coordinates are skipped; `index` is the post-skip position
+ * Map proxy fire records into internal fire records. Records with missing,
+ * non-numeric or out-of-range (WGS84) coordinates are skipped; `index` is the post-skip position
  * (it keys pick ids and context-store ids, so it must stay sequential).
  * `contextEntity`/`position` start null and are lazily filled by the layer.
  * @param {?Array<Object>} records - /api/firms `fires` array.
@@ -21,7 +21,15 @@ export function adaptFirmsRecords(records) {
   for (const record of records) {
     const lat = Number(record?.lat);
     const lon = Number(record?.lon);
-    if (!Number.isFinite(lat) || !Number.isFinite(lon)) continue;
+    if (
+      !hasCoordinateValue(record?.lat) ||
+      !hasCoordinateValue(record?.lon) ||
+      !Number.isFinite(lat) ||
+      !Number.isFinite(lon) ||
+      Math.abs(lat) > 90 ||
+      Math.abs(lon) > 180
+    )
+      continue;
     fires.push({
       index: fires.length,
       lat,
@@ -110,3 +118,11 @@ function finiteNumber(value) {
   const number = Number(value);
   return Number.isFinite(number) ? number : 0;
 }
+
+// Same rule as parseFirmsCsv: a blank or non-numeric value is not a zero.
+function hasCoordinateValue(value) {
+  return (
+    typeof value === 'number' ||
+    (typeof value === 'string' && value.trim() !== '')
+  );
+}

src/data/firmsCsv.js

@@ -105,7 +105,17 @@ export function parseFirmsCsv(text) {
     if (parts.length < header.length) continue; // malformed row — skip
     const lat = Number(parts[iLat]);
     const lon = Number(parts[iLon]);
-    if (!Number.isFinite(lat) || !Number.isFinite(lon)) continue;
+    // Blank or out-of-range positions are dropped, never read as 0 (see
+    // hasCoordinateValue in firmsAdapt.js for the proxy-record side).
+    if (
+      !parts[iLat].trim() ||
+      !parts[iLon].trim() ||
+      !Number.isFinite(lat) ||
+      !Number.isFinite(lon) ||
+      Math.abs(lat) > 90 ||
+      Math.abs(lon) > 180
+    )
+      continue;
 
     records.push({
       lat,

src/data/flights.test.mjs

@@ -79,6 +79,12 @@ test('flights analyst record: full record maps every contract field', () => {
     aircraftClass: 'airliner',
     originCountry: 'United States',
     operator: 'Southwest Airlines',
+    squawk: null,
+    emergency: false,
+    emergencyKind: null,
+    emergencySource: null,
+    emergencyBroadcast: null,
+    lastContactAtMs: null,
     routeOrigin: 'AUS',
     routeDestination: 'LAX',
   });

src/data/gnssIntegrityProxy.test.mjs

@@ -0,0 +1,429 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  gnssIntegrityAnchor,
+  gnssIntegrityProxy,
+  gnssRetryCooldownMs,
+} from '../../server/providers/gnssIntegrity.js';
+
+const snapshot = {
+  now: 4_000_000_000_000,
+  ac: [
+    {
+      hex: '4ca7b5',
+      type: 'adsb_icao',
+      version: 2,
+      alt_baro: 36000,
+      lat: 50.1,
+      lon: 19.9,
+      nic: 0,
+      nac_p: 0,
+      seen_pos: 1,
+      flight: 'RYR1AB  ',
+      r: 'EI-ABC',
+    },
+    { hex: '000001', type: 'mlat', lat: 50, lon: 20, nic: 0, nac_p: 0 },
+  ],
+};
+
+function install(options = {}, hook = 'configureServer') {
+  let handler;
+  const plugin = gnssIntegrityProxy({ monotonicNow: options.now, ...options });
+  assert.equal(plugin.name, 'gnss-integrity');
+  plugin[hook]({
+    middlewares: {
+      use(path, callback) {
+        assert.equal(path, '/api/gnss-integrity');
+        handler = callback;
+      },
+    },
+  });
+  return async (url = '/?lat=50&lon=20', method = 'GET', peer = 'local') => {
+    const res = {
+      writeHead(status, headers) {
+        this.status = status;
+        this.headers = headers;
+      },
+      end(body) {
+        this.body = JSON.parse(body);
+      },
+    };
+    await handler({ url, method, socket: { remoteAddress: peer } }, res);
+    return res;
+  };
+}
+
+test('anchors snap to whole degrees and reject missing or out-of-range values', () => {
+  assert.deepEqual(gnssIntegrityAnchor('/?lat=50.44&lon=19.51'), {
+    lat: 50,
+    lon: 20,
+  });
+  assert.equal(gnssIntegrityAnchor('/?lat=91&lon=0'), null);
+  assert.equal(gnssIntegrityAnchor('/?lat=0&lon=-181'), null);
+  assert.equal(gnssIntegrityAnchor('/?lat=0'), null);
+  assert.equal(gnssIntegrityAnchor('/?lat=abc&lon=1'), null);
+});
+
+for (const hook of ['configureServer', 'configurePreviewServer']) {
+  test(`${hook}: fetches the fixed adsb.lol origin and returns only integrity facts`, async () => {
+    const calls = [];
+    const request = install(
+      {
+        now: () => 1234,
+        fetchImpl: async (url, options) => {
+          calls.push(url);
+          assert.ok(options.signal instanceof AbortSignal);
+          assert.equal(options.redirect, 'error');
+          return Response.json(snapshot);
+        },
+      },
+      hook,
+    );
+    const res = await request(
+      '/?lat=50.2&lon=19.8&url=https://invalid.example',
+    );
+    assert.equal(res.status, 200);
+    assert.deepEqual(calls, ['https://api.adsb.lol/v2/lat/50/lon/20/dist/250']);
+    assert.deepEqual(res.body, {
+      fetchedAt: 1234,
+      ageMs: 0,
+      anchor: { lat: 50, lon: 20 },
+      radiusNm: 250,
+      classifier: 'gev-nic-nacp-v2',
+      rows: [
+        {
+          hex: '4ca7b5',
+          lat: 50.1,
+          lon: 19.9,
+          nic: 0,
+          nacp: 0,
+          gpsLost: false,
+          degraded: true,
+        },
+      ],
+    });
+    assert.equal(res.headers['Cache-Control'], 'no-store');
+  });
+}
+
+test('snapshots are cached per anchor and concurrent reads share one upstream call', async () => {
+  let clock = 0;
+  let calls = 0;
+  const request = install({
+    now: () => clock,
+    fetchImpl: async () => {
+      calls += 1;
+      return Response.json(snapshot);
+    },
+  });
+  await Promise.all([request(), request('/?lat=50.3&lon=20.2')]);
+  assert.equal(calls, 1);
+  clock = 59_000;
+  const cached = await request();
+  assert.equal(calls, 1);
+  assert.equal(cached.body.fetchedAt, 0);
+  assert.equal(
+    cached.body.ageMs,
+    59_000,
+    'a cached answer reports its age on the server clock',
+  );
+  clock = 61_000;
+  await request();
+  assert.equal(calls, 2);
+  await request('/?lat=10&lon=10');
+  assert.equal(calls, 3);
+});
+
+test('an upstream failure serves the last snapshot as stale, else 502', async () => {
+  let clock = 0;
+  let fail = false;
+  const request = install({
+    now: () => clock,
+    fetchImpl: async () =>
+      fail ? new Response('down', { status: 503 }) : Response.json(snapshot),
+  });
+  await request();
+  fail = true;
+  clock = 120_000;
+  const stale = await request();
+  assert.equal(stale.status, 200);
+  assert.equal(stale.body.stale, true);
+  assert.equal(
+    stale.body.fetchedAt,
+    0,
+    'a stale answer keeps the time it was observed',
+  );
+  assert.equal(stale.body.ageMs, 120_000);
+  assert.equal(stale.headers['X-Data-Stale'], 'true');
+  const missing = await request('/?lat=-10&lon=-10');
+  assert.equal(missing.status, 502);
+  assert.deepEqual(missing.body, { error: 'gnss_integrity_unavailable' });
+});
+
+test('a stale snapshot older than the layer window is no longer served', async () => {
+  let clock = 0;
+  let fail = false;
+  const request = install({
+    now: () => clock,
+    fetchImpl: async () =>
+      fail ? new Response('down', { status: 503 }) : Response.json(snapshot),
+  });
+  await request();
+  fail = true;
+  clock = 30 * 60_000;
+  assert.equal((await request()).status, 200);
+  clock = 30 * 60_000 + 1;
+  const expired = await request();
+  assert.equal(expired.status, 502);
+  assert.deepEqual(expired.body, { error: 'gnss_integrity_unavailable' });
+});
+
+test('an upstream 429 starts a cooldown with no further upstream calls', async () => {
+  let clock = 0;
+  let calls = 0;
+  const request = install({
+    now: () => clock,
+    fetchImpl: async () => {
+      calls += 1;
+      return new Response('slow down', {
+        status: 429,
+        headers: { 'retry-after': '90' },
+      });
+    },
+  });
+  const first = await request();
+  assert.equal(first.status, 429);
+  assert.equal(first.headers['Retry-After'], '90');
+  clock = 30_500;
+  const cooling = await request('/?lat=1&lon=1');
+  assert.equal(cooling.status, 429);
+  // The browser is told the remaining shared cooldown, rounded up.
+  assert.equal(cooling.headers['Retry-After'], '60');
+  assert.equal(calls, 1);
+  clock = 91_000;
+  await request('/?lat=2&lon=2');
+  assert.equal(calls, 2);
+});
+
+test('Retry-After accepts sane seconds or HTTP dates up to one hour', () => {
+  const nowMs = Date.parse('2026-09-29T12:00:00Z');
+  assert.equal(gnssRetryCooldownMs('30', nowMs), 30_000);
+  assert.equal(gnssRetryCooldownMs('1', nowMs), 5_000);
+  assert.equal(gnssRetryCooldownMs('3600', nowMs), 3_600_000);
+  assert.equal(
+    gnssRetryCooldownMs('Tue, 29 Sep 2026 13:00:00 GMT', nowMs),
+    3_600_000,
+  );
+  assert.equal(gnssRetryCooldownMs('1e309', nowMs), 60_000);
+  assert.equal(
+    gnssRetryCooldownMs('Tue, 29 Sep 2026 12:00:45 GMT', nowMs),
+    45_000,
+  );
+  // Garbage, a past date or no header fall back to the default minute.
+  assert.equal(gnssRetryCooldownMs('soon', nowMs), 60_000);
+  assert.equal(
+    gnssRetryCooldownMs('Tue, 29 Sep 2026 11:00:00 GMT', nowMs),
+    60_000,
+  );
+  assert.equal(gnssRetryCooldownMs(null, nowMs), 60_000);
+});
+
+test('overlapping 429s preserve the longest shared deadline', async () => {
+  let clock = 0,
+    calls = 0;
+  const pending = [];
+  const request = install({
+    now: () => clock,
+    fetchImpl: () => {
+      calls += 1;
+      return new Promise((resolve) => pending.push(resolve));
+    },
+  });
+  const long = request('/?lat=1&lon=0'),
+    short = request('/?lat=2&lon=0');
+  await new Promise((resolve) => setImmediate(resolve));
+  pending[0](
+    new Response('', { status: 429, headers: { 'Retry-After': '3600' } }),
+  );
+  assert.equal((await long).headers['Retry-After'], '3600');
+  clock = 1000;
+  pending[1](
+    new Response('', { status: 429, headers: { 'Retry-After': '5' } }),
+  );
+  assert.equal((await short).headers['Retry-After'], '3599');
+  clock = 7000;
+  assert.equal((await request('/?lat=3&lon=0')).status, 429);
+  assert.equal(calls, 2);
+  clock = 3_600_001;
+  const resumed = request('/?lat=3&lon=0');
+  await new Promise((resolve) => setImmediate(resolve));
+  pending[2](Response.json(snapshot));
+  assert.equal((await resumed).status, 200);
+  assert.equal(calls, 3);
+});
+
+test('a cached anchor keeps serving its last snapshot as stale during a cooldown', async () => {
+  let clock = 0;
+  let limited = false;
+  let calls = 0;
+  const request = install({
+    now: () => clock,
+    fetchImpl: async () => {
+      calls += 1;
+      return limited
+        ? new Response('slow down', { status: 429 })
+        : Response.json(snapshot);
+    },
+  });
+  await request();
+  limited = true;
+  clock = 61_000;
+  // Another anchor trips the shared cooldown…
+  assert.equal((await request('/?lat=5&lon=5')).status, 429);
+  clock = 62_000;
+  // …and the cached anchor is answered from cache without an upstream call.
+  const stale = await request();
+  assert.equal(stale.status, 200);
+  assert.equal(stale.body.stale, true);
+  assert.equal(stale.body.rows.length, 1);
+  assert.equal(calls, 2);
+});
+
+test('an oversized upstream body is refused as 502 without being parsed', async () => {
+  const request = install({
+    fetchImpl: async () =>
+      new Response('{}', {
+        headers: { 'content-length': String(9 * 1024 * 1024) },
+      }),
+  });
+  const res = await request();
+  assert.equal(res.status, 502);
+  assert.deepEqual(res.body, { error: 'gnss_integrity_unavailable' });
+});
+
+test('the route rejects other methods, paths, bad anchors, a malformed feed and floods', async () => {
+  const request = install({
+    fetchImpl: async () => Response.json({ nope: true }),
+  });
+  assert.equal((await request('/', 'POST')).status, 405);
+  assert.equal((await request('/other?lat=1&lon=1')).status, 404);
+  assert.equal((await request('/?lat=1')).status, 400);
+  assert.equal((await request('/?lat=1&lon=1')).status, 502);
+  const flood = install({ fetchImpl: async () => Response.json(snapshot) });
+  let limited = 0;
+  for (let i = 0; i < 40; i += 1)
+    if ((await flood(`/?lat=${i}&lon=1`, 'GET', 'flood')).status === 429)
+      limited += 1;
+  assert.ok(limited > 0);
+});
+
+test('GERMAN: pathological retry deadlines are bounded', () => {
+  const at = Date.parse('2026-10-14T12:00:00Z');
+  assert.ok(gnssRetryCooldownMs('1e305', at) <= 3600000);
+  assert.equal(gnssRetryCooldownMs('9999999999999999999999', at), 3600000);
+  assert.equal(
+    gnssRetryCooldownMs('Wed, 14 Oct 2099 12:00:00 GMT', at),
+    3600000,
+  );
+  assert.equal(gnssRetryCooldownMs('0x10', at), 60000);
+});
+
+test('GERMAN: 5xx, network timeouts and malformed JSON share a short cooldown', async () => {
+  for (const fail of [
+    async () => new Response('', { status: 503 }),
+    async () => {
+      throw new DOMException('timeout', 'TimeoutError');
+    },
+    async () => new Response('bad JSON'),
+  ]) {
+    let clock = 0,
+      calls = 0;
+    const request = install({
+      now: () => clock,
+      fetchImpl: async () => {
+        calls++;
+        return fail();
+      },
+    });
+    assert.equal((await request()).status, 502);
+    clock = 14000;
+    assert.equal((await request('/?lat=1&lon=1')).status, 502);
+    assert.equal(calls, 1);
+    clock = 15001;
+    await request('/?lat=2&lon=2');
+    assert.equal(calls, 2);
+  }
+});
+
+test('GERMAN: source timestamp dates evidence; frozen old snapshots are rejected', async () => {
+  const now = 1800000000000;
+  const request = install({
+    now: () => now,
+    fetchImpl: async () =>
+      Response.json({ ...snapshot, now: (now - 120000) / 1000 }),
+  });
+  const res = await request();
+  assert.equal(res.body.ageMs, 120000);
+  assert.equal(res.body.stale, true);
+  for (const sourceNow of [(now - 1800001) / 1000, undefined, NaN]) {
+    const missing = install({
+      now: () => now,
+      fetchImpl: async () => Response.json({ ...snapshot, now: sourceNow }),
+    });
+    assert.equal((await missing()).status, 502);
+  }
+});
+
+test('GERMAN: cache age and cooldown remain stable across a wall-clock rollback', async () => {
+  let wall = 1800000000000,
+    mono = 0,
+    calls = 0;
+  const request = install({
+    now: () => wall,
+    monotonicNow: () => mono,
+    fetchImpl: async () => {
+      calls++;
+      return calls === 1
+        ? Response.json({ ...snapshot, now: wall / 1000 })
+        : new Response('', { status: 429, headers: { 'Retry-After': '60' } });
+    },
+  });
+  await request();
+  wall -= 3600000;
+  mono = 61000;
+  const stale = await request();
+  assert.equal(stale.body.ageMs, 61000);
+  assert.equal(stale.body.stale, true);
+  mono += 1000;
+  assert.equal((await request('/?lat=1&lon=1')).headers['Retry-After'], '59');
+  assert.equal(calls, 2);
+});
+
+test('GERMAN: cache hits and coalesced reads do not consume upstream admission', async () => {
+  let calls = 0;
+  const request = install({
+    now: () => 1800000000000,
+    fetchImpl: async () => {
+      calls++;
+      return Response.json(snapshot);
+    },
+  });
+  for (let i = 0; i < 100; i++) assert.equal((await request()).status, 200);
+  assert.equal((await request('/?lat=1&lon=1')).status, 200);
+  assert.equal(calls, 2);
+});
+
+test('GERMAN: distinct concurrent upstream reads are bounded', async () => {
+  const pending = [];
+  const request = install({
+    fetchImpl: () => new Promise((resolve) => pending.push(resolve)),
+  });
+  const jobs = Array.from({ length: 30 }, (_, i) =>
+    request(`/?lat=${i}&lon=1`),
+  );
+  await new Promise((resolve) => setImmediate(resolve));
+  assert.ok(pending.length <= 8);
+  pending.forEach((resolve) => resolve(Response.json(snapshot)));
+  const results = await Promise.all(jobs);
+  assert.ok(results.some((result) => result.status === 429));
+});

src/data/layerState.js

@@ -607,6 +607,11 @@ export const LAYER_STATE_REGISTRY = Object.freeze([
     disposition: 'enabled+options',
     optionOwner: 'flights',
   }),
+  Object.freeze({
+    id: 'gnss-integrity',
+    token: '3',
+    disposition: 'enabled-only',
+  }),
   Object.freeze({ id: 'local-dams', token: 'q', disposition: 'enabled-only' }),
   Object.freeze({
     id: 'local-datacenters',

src/data/layerState.test.mjs

@@ -202,8 +202,8 @@ function encode(state) {
 
 test('production registry is exact, canonical, and rejects incomplete contracts', async () => {
   assert.equal(validateLayerStateRegistry(), true);
-  assert.equal(REGISTERED_LAYER_IDS.length, 29);
-  assert.equal(new Set(REGISTERED_LAYER_IDS).size, 29);
+  assert.equal(REGISTERED_LAYER_IDS.length, 30);
+  assert.equal(new Set(REGISTERED_LAYER_IDS).size, 30);
   assert.ok(REGISTERED_LAYER_IDS.includes('transit'));
   assert.deepEqual(REGISTERED_LAYER_IDS, [...REGISTERED_LAYER_IDS].sort());
   assert.deepEqual(LEGACY_LAYER_STATE_TOKENS, {
@@ -242,19 +242,19 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   for (const [id, token] of Object.entries(LEGACY_LAYER_STATE_TOKENS)) {
     assert.equal(LAYER_STATE_TOKEN_RESERVATIONS[id], token);
   }
-  assert.equal(nextLayerStateToken(), '3');
+  assert.equal(nextLayerStateToken(), '4');
   assert.equal(
     nextLayerStateToken({
       ...LAYER_STATE_TOKEN_RESERVATIONS,
-      alpha: '3',
-      bravo: '4',
+      alpha: '4',
+      bravo: '5',
     }),
-    '5',
+    '6',
   );
   const digitsExhausted = {
     ...LAYER_STATE_TOKEN_RESERVATIONS,
     ...Object.fromEntries(
-      [...'3456789'].map((digit) => [`prior-${digit}`, digit]),
+      [...'456789'].map((digit) => [`prior-${digit}`, digit]),
     ),
   };
   assert.equal(nextLayerStateToken(digitsExhausted), '00');
@@ -307,8 +307,8 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   assert.equal(
     validateLayerStateAllocations(LAYER_STATE_TOKEN_RESERVATIONS, {
       ...LAYER_STATE_TOKEN_RESERVATIONS,
-      future: '3',
-      next: '4',
+      future: '4',
+      next: '5',
     }),
     true,
   );
@@ -318,7 +318,7 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
         ...LAYER_STATE_TOKEN_RESERVATIONS,
         future: '00',
       }),
-    /next free token 3/,
+    /next free token 4/,
   );
   const beforeLastDigit = { ...digitsExhausted };
   delete beforeLastDigit['prior-9'];
@@ -341,10 +341,10 @@ test('production registry is exact, canonical, and rejects incomplete contracts'
   assert.throws(
     () =>
       validateLayerStateAllocations(
-        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '3' },
-        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '3', competing: '3' },
+        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '4' },
+        { ...LAYER_STATE_TOKEN_RESERVATIONS, merged: '4', competing: '4' },
       ),
-    /next free token 4/,
+    /next free token 5/,
   );
   assert.throws(
     () => validateLayerStateAllocations({ future: '00' }, { future: '01' }),
@@ -2639,6 +2639,23 @@ test('the recent-imagery split is share-link only: never stored locally, and a s
   );
 });
 
+test('GNSS interference uses digit 3 without colliding with other digit tokens', () => {
+  const decoded = decodeLayerStateParams(new URLSearchParams('v=2&l=3.2.1'));
+  assert.deepEqual(decoded.enabledLayerIds, [
+    'fire-perimeters',
+    'gnss-integrity',
+    'recent-imagery',
+  ]);
+  assert.equal(
+    LAYER_STATE_REGISTRY.find(({ id }) => id === 'gnss-integrity').token,
+    '3',
+  );
+  assert.deepEqual(
+    decodeLayerStateParams(new URLSearchParams(encode(decoded))),
+    decoded,
+  );
+});
+
 test('fire perimeters uses digit 2 without colliding with wind or recent imagery', () => {
   const decoded = decodeLayerStateParams(new URLSearchParams('v=2&l=2.k.1'));
   assert.deepEqual(decoded.enabledLayerIds, [

src/data/layerStateTokenLedger.test.mjs

@@ -128,10 +128,14 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
     { ...parseLayerStateTokenReservations(reservationRows) },
     { ...LAYER_STATE_TOKEN_RESERVATIONS },
   );
-  assert.equal(Object.keys(LAYER_STATE_TOKEN_RESERVATIONS).length, 29);
+  assert.equal(Object.keys(LAYER_STATE_TOKEN_RESERVATIONS).length, 30);
   assert.deepEqual(
     { ...LAYER_STATE_TOKEN_RESERVATIONS },
-    { ...LEGACY_LAYER_STATE_TOKENS, 'street-level': '0' },
+    {
+      ...LEGACY_LAYER_STATE_TOKENS,
+      'street-level': '0',
+      'gnss-integrity': '3',
+    },
   );
   assert.throws(
     () => parseLayerStateTokenReservations(reservationRows.slice(1)),
@@ -151,9 +155,9 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
     /Duplicate layer-state token reservation/,
   );
   assert.equal(
-    parseLayerStateTokenReservations([...reservationRows, ['future', '3']])
+    parseLayerStateTokenReservations([...reservationRows, ['future', '4']])
       .future,
-    '3',
+    '4',
   );
   assert.throws(
     () =>
@@ -171,14 +175,14 @@ test('reservation ledger is complete, pinned, and rejects duplicate or malformed
 
 test('published retired digits and competing PRs advance the merge-time allocation', () => {
   withPublishedBase(
-    { rows: [...reservationRows, ['retired-layer', '3']] },
+    { rows: [...reservationRows, ['retired-layer', '4']] },
     (cwd) => {
       const published = readPublishedLayerStateReservations('HEAD', cwd);
-      assert.equal(nextLayerStateToken(published), '4');
+      assert.equal(nextLayerStateToken(published), '5');
       assert.equal(
         validateLayerStateAllocations(published, {
           ...published,
-          newcomer: '4',
+          newcomer: '5',
         }),
         true,
       );
@@ -186,15 +190,15 @@ test('published retired digits and competing PRs advance the merge-time allocati
         () =>
           validateLayerStateAllocations(published, {
             ...published,
-            competing: '3',
+            competing: '4',
           }),
-        /next free token 4/,
+        /next free token 5/,
       );
       assert.throws(
         () =>
           validateLayerStateAllocations(published, {
             ...LAYER_STATE_TOKEN_RESERVATIONS,
-            newcomer: '3',
+            newcomer: '4',
           }),
         /changed or removed: retired-layer/,
       );
@@ -202,8 +206,8 @@ test('published retired digits and competing PRs advance the merge-time allocati
   );
 });
 
-test('PR B manually replaces provisional 3 with 4 after PR A publishes 3', () => {
-  withPublishedBase({ rows: [...reservationRows, ['pr-a', '3']] }, (cwd) => {
+test('PR B manually replaces provisional 4 with 5 after PR A publishes 4', () => {
+  withPublishedBase({ rows: [...reservationRows, ['pr-a', '4']] }, (cwd) => {
     mkdirSync(path.join(cwd, 'scripts'));
     const fixtureChecker = path.join(
       cwd,
@@ -224,8 +228,8 @@ test('PR B manually replaces provisional 3 with 4 after PR A publishes 3', () =>
 
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-b', '3']],
-      [{ id: 'pr-b', token: '3' }],
+      [...reservationRows, ['pr-b', '4']],
+      [{ id: 'pr-b', token: '4' }],
     );
     const beforeRebase = runCheck();
     assert.equal(beforeRebase.status, 1);
@@ -233,10 +237,10 @@ test('PR B manually replaces provisional 3 with 4 after PR A publishes 3', () =>
 
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-a', '3'], ['pr-b', '3']],
+      [...reservationRows, ['pr-a', '4'], ['pr-b', '4']],
       [
-        { id: 'pr-a', token: '3' },
-        { id: 'pr-b', token: '3' },
+        { id: 'pr-a', token: '4' },
+        { id: 'pr-b', token: '4' },
       ],
     );
     const staleRebase = runCheck();
@@ -244,16 +248,16 @@ test('PR B manually replaces provisional 3 with 4 after PR A publishes 3', () =>
     assert.match(staleRebase.stderr, /Duplicate layer-state token reservation/);
 
     const published = readPublishedLayerStateReservations('HEAD', cwd);
-    assert.equal(nextLayerStateToken(published), '4');
-    const validBaselineRows = [...reservationRows, ['pr-a', '3']];
-    writeCodecFixture(cwd, validBaselineRows, [{ id: 'pr-a', token: '3' }]);
+    assert.equal(nextLayerStateToken(published), '5');
+    const validBaselineRows = [...reservationRows, ['pr-a', '4']];
+    writeCodecFixture(cwd, validBaselineRows, [{ id: 'pr-a', token: '4' }]);
     const helper = spawnSync(
       process.execPath,
       [realpathSync(fixtureNext), 'pr-b'],
       { cwd, encoding: 'utf8' },
     );
     assert.equal(helper.status, 0, helper.stderr);
-    assert.match(helper.stdout, /pr-b: 4/);
+    assert.match(helper.stdout, /pr-b: 5/);
     assert.deepEqual(
       JSON.parse(readFileSync(path.join(cwd, LEDGER_PATH), 'utf8')),
       validBaselineRows,
@@ -261,20 +265,20 @@ test('PR B manually replaces provisional 3 with 4 after PR A publishes 3', () =>
     );
     writeCodecFixture(
       cwd,
-      [...reservationRows, ['pr-a', '3'], ['pr-b', '4']],
+      [...reservationRows, ['pr-a', '4'], ['pr-b', '5']],
       [
-        { id: 'pr-a', token: '3' },
-        { id: 'pr-b', token: '4' },
+        { id: 'pr-a', token: '4' },
+        { id: 'pr-b', token: '5' },
       ],
     );
     const corrected = runCheck();
     assert.equal(corrected.status, 0, corrected.stderr);
-    assert.match(corrected.stdout, /30 published, 1 new/);
+    assert.match(corrected.stdout, /31 published, 1 new/);
   });
 });
 
 test('allocation batches cross the last digit and base-36 pair boundaries in order', () => {
-  const digitRows = [...'3456789'].map((digit) => [`retired-${digit}`, digit]);
+  const digitRows = [...'456789'].map((digit) => [`retired-${digit}`, digit]);
   const allDigits = parseLayerStateTokenReservations([
     ...reservationRows,
     ...digitRows,
@@ -326,7 +330,7 @@ test('allocation batches cross the last digit and base-36 pair boundaries in ord
 test('an isolated valid two-character fixture round-trips an l field beyond the old 64-character cap', async () => {
   const cwd = mkdtempSync(path.join(tmpdir(), 'gev-layer-token-width-'));
   try {
-    const priorDigits = [...'3456789'].map((digit) => [
+    const priorDigits = [...'456789'].map((digit) => [
       `qa-prior-digit-${digit}`,
       digit,
     ]);
@@ -363,7 +367,7 @@ test('an isolated valid two-character fixture round-trips an l field beyond the
     const params = new URLSearchParams([['v', '2']]);
     codec.encodeLayerStateParams(params, state);
     assert.ok(params.get('l').length > 64, 'fixture must cross the old cap');
-    assert.equal(params.get('l').length, 69);
+    assert.equal(params.get('l').length, 71);
     const restored = codec.decodeLayerStateParams(params);
     assert.deepEqual(restored?.enabledLayerIds, expectedLayerIds);
     assert.deepEqual(restored?.options, state.options);
@@ -381,7 +385,7 @@ test('checker reads a complete future base ledger and rejects retired-token reus
     },
     (cwd) => {
       const published = readPublishedLayerStateReservations('HEAD', cwd);
-      assert.equal(Object.keys(published).length, 30);
+      assert.equal(Object.keys(published).length, 31);
       assert.equal(published['retired-layer'], '00');
       assert.throws(
         () =>

src/data/layerStateTokenReservations.json

@@ -9,6 +9,7 @@
   ["earthquakes", "e"],
   ["fire-perimeters", "2"],
   ["flights", "f"],
+  ["gnss-integrity", "3"],
   ["local-dams", "q"],
   ["local-datacenters", "d"],
   ["local-firms", "w"],

src/data/militaryFlights.test.mjs

@@ -71,6 +71,12 @@ test('military analyst record: full record maps every contract field', () => {
     aircraftClass: 'widebody',
     originCountry: null,
     operator: 'United States Air Force',
+    squawk: null,
+    emergency: false,
+    emergencyKind: null,
+    emergencySource: null,
+    emergencyBroadcast: null,
+    lastContactAtMs: null,
     routeOrigin: null,
     routeDestination: null,
   });

src/director/packs/asset-stream-cancellation.test.mjs

@@ -0,0 +1,79 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { createAssetDirectorySource } from './source.js';
+test('cancellation during the terminating read cannot return a scene asset', async () => {
+  for (const cancel of [true, false]) {
+    const controller = new AbortController();
+    let reads = 0,
+      cancelled = 0,
+      released = 0;
+    const source = createAssetDirectorySource({
+      baseUrl: 'https://fixture.example/assets/',
+      fetchImpl: async () => ({
+        ok: true,
+        headers: new Headers({ 'content-type': 'application/octet-stream' }),
+        body: {
+          getReader() {
+            return {
+              async read() {
+                reads++;
+                if (reads === 1)
+                  return { done: false, value: new Uint8Array([1, 2]) };
+                if (cancel) controller.abort();
+                return { done: true };
+              },
+              async cancel() {
+                cancelled++;
+              },
+              releaseLock() {
+                released++;
+              },
+            };
+          },
+        },
+      }),
+    });
+    const pending = source({ path: 'scene.bin', signal: controller.signal });
+    if (cancel) await assert.rejects(pending, { name: 'AbortError' });
+    else assert.deepEqual([...(await pending).bytes], [1, 2]);
+    assert.equal(cancelled, 1);
+    assert.equal(released, 1);
+  }
+});
+
+test('cancellation during reader cleanup cannot return a scene asset', async () => {
+  const controller = new AbortController();
+  const reason = new DOMException('scene changed', 'AbortError');
+  let released = 0;
+  const source = createAssetDirectorySource({
+    baseUrl: 'https://fixture.example/assets/',
+    fetchImpl: async () => ({
+      ok: true,
+      headers: new Headers(),
+      body: {
+        getReader() {
+          let reads = 0;
+          return {
+            async read() {
+              reads++;
+              return reads === 1
+                ? { done: false, value: new Uint8Array([1]) }
+                : { done: true };
+            },
+            async cancel() {
+              controller.abort(reason);
+            },
+            releaseLock() {
+              released++;
+            },
+          };
+        },
+      },
+    }),
+  });
+  await assert.rejects(
+    source({ path: 'scene.bin', signal: controller.signal }),
+    (error) => error === reason,
+  );
+  assert.equal(released, 1);
+});

src/director/packs/source.js

@@ -41,6 +41,7 @@ export function createAssetDirectorySource({
       for (;;) {
         signal?.throwIfAborted();
         const { done, value } = await reader.read();
+        signal?.throwIfAborted();
         if (done) break;
         length += value.byteLength;
         if (length > maxBytes) throw new Error('Asset exceeds byte limit');
@@ -50,6 +51,8 @@ export function createAssetDirectorySource({
       await reader.cancel().catch(() => {});
       reader.releaseLock();
     }
+    // Cleanup awaits too; a cancel during it must still discard the asset.
+    signal?.throwIfAborted();
     const bytes = new Uint8Array(length);
     let offset = 0;
     for (const chunk of chunks) {

src/firstRunExperience.test.mjs

@@ -673,11 +673,11 @@ test('the voice TOOL SCHEMA matches the pinned contract — the mission mapping
   // referent-only track_entity alternative (kept out of the model-facing
   // schema, which may not carry top-level anyOf), and Contacts requested-radius
   // list descriptions; the missions still ride existing tools.
-  // Street Level adds toggle enum values and the generated alias hint.
-  assert.equal(block.length, 29802, 'serialized tool schema length drifted');
+  // Street Level and GNSS extend the manifest; broadcast caveats describe tracked and analyst aircraft.
+  assert.equal(block.length, 30511, 'serialized tool schema length drifted');
   assert.equal(
     crypto.createHash('sha256').update(block).digest('hex'),
-    'b316ca2e67848eb565b6847ac044a19d1465d8ef8252a5dfbd7d947a2a36d5ed',
+    '62d5df9cedf413403e4fd0a7cbe94bb2cd13736c3d8fedc84bcccd63ad253eb6',
     'the first-run missions must ride EXISTING tools: no schema edit, no cache bust',
   );
   const instructions = fs.readFileSync(new URL('../server/providers/openai/instructions.js', import.meta.url), 'utf8');

src/layers/flights/policy.js

@@ -7,6 +7,7 @@ export {
   ERROR_BACKOFF_INTERVAL,
 } from './recordPolicy.js';
 import * as Cesium from 'cesium';
+import { EMERGENCY_TINT_CSS } from '../../data/aircraftEmergency.js';
 
 export const FOCUS_EVIDENCE_DEV = import.meta.env?.DEV === true;
 
@@ -14,6 +15,11 @@ export const FOCUS_EVIDENCE_DEV = import.meta.env?.DEV === true;
 
 export const MIL_TINT = Cesium.Color.fromCssColorString('#FFB800');
 
+/** Red tint for aircraft broadcasting an emergency (7500/7600/7700 or ADS-B status). */
+
+export const EMERGENCY_TINT =
+  Cesium.Color.fromCssColorString(EMERGENCY_TINT_CSS);
+
 // --- Ground traffic (owner reversal 2026-07-03: "absolutely we should see planes
 // taxiing and landing") -----------------------------------------------------------
 // Present-but-grounded planes are RENDERED instead of being skipped: same class

src/layers/flights/queries.js

@@ -15,6 +15,7 @@ import {
   FOCUS_EVIDENCE_DEV,
   FLEET_DR_INTERVAL_MS,
 } from './policy.js';
+import { emergencyBroadcastPhrase } from '../../data/aircraftEmergency.js';
 
 export function createQueries({
   flightState,
@@ -167,6 +168,10 @@ export function createQueries({
         flightState.records.missingPolls.get(icao24) ||
         flightState.feed._backoff,
       ),
+      // This poll's transponder broadcast (not sticky; see records.js).
+      squawk: info?.squawk ?? null,
+      emergency: info?.emergency ? { ...info.emergency } : null,
+      emergencyBroadcast: emergencyBroadcastPhrase(info?.emergency),
       airline: info?.airline ?? null,
       // CLASS label follows the TR-3B conversion so every downstream card
       // (cockpit, Contacts, analyst) agrees with the triangle on screen.
@@ -219,7 +224,10 @@ export function createQueries({
    *   lon: number|null, altitudeM: number|null, speedMps: number|null,
    *   heading: number|null, verticalRateMps: number|null, onGround: boolean,
    *   military: boolean, aircraftClass: string|null, originCountry: string|null,
-   *   operator: string|null, routeOrigin: string|null, routeDestination: string|null}}
+   *   operator: string|null, squawk: string|null, emergency: boolean,
+   *   emergencyKind: string|null, emergencySource: 'squawk'|'ads-b'|null,
+   *   emergencyBroadcast: string|null, lastContactAtMs: number|null, routeOrigin: string|null,
+   *   routeDestination: string|null}}
    */
 
   function mapAnalystRecord(
@@ -253,6 +261,20 @@ export function createQueries({
       aircraftClass: tr3bAircraftClass(icao24, text(info?.klass)),
       originCountry: text(info?.originCountry),
       operator: text(info?.airline),
+      squawk: text(info?.squawk),
+      // True while this poll broadcast an emergency (7500/7600/7700 or the
+      // ADS-B status); priority statuses (lifeguard, minfuel) report the kind
+      // without the flag.
+      emergency: info?.emergency?.severity === 'emergency',
+      emergencyKind: text(info?.emergency?.kind),
+      // Provenance, so a summary can say "broadcasting squawk 7700" rather
+      // than "ADS-B reports general emergency" (or flatten both): 'squawk'
+      // when the Mode A code names the status, 'ads-b' for the readsb field.
+      emergencySource: text(info?.emergency?.source),
+      emergencyBroadcast: emergencyBroadcastPhrase(info?.emergency),
+      // Latest known general aircraft-message contact, retained if a poll
+      // has no time. This is not the receipt time of the current status.
+      lastContactAtMs: num(info?.lastContactEpochMs),
       routeOrigin: routeOk ? text(info?.route?.origin?.code) : null,
       routeDestination: routeOk ? text(info?.route?.destination?.code) : null,
     };

src/layers/flights/records.js

@@ -4,6 +4,7 @@ import {
   pickRenderAltitudeM,
 } from '../../data/renderAltitude.js';
 import { classifyAircraft } from '../../data/aircraftClass.js';
+import { aircraftEmergency } from '../../data/aircraftEmergency.js';
 import {
   approxDistanceKm,
   GROUND_FLOOR_CLAMP_RADIUS_KM,
@@ -226,6 +227,22 @@ export class FlightRecords {
       // like callsign so a transient blank row doesn't blank the field.
       originCountry:
         stickyText(origin_country, prevMeta?.originCountry) || null,
+      // Per poll, NOT sticky: an emergency code clears when the crew resets
+      // it, so a blank squawk must not hold a stale 7700 on screen.
+      squawk: observation.squawk ?? null,
+      // One source-switch omission may retain an ADS-B status, while an
+      // explicit clear or changed squawk always takes effect immediately.
+      emergency:
+        observation.emergency === undefined &&
+        observation.squawk === prevMeta?.squawk &&
+        prevMeta?.emergency?.source === 'ads-b' &&
+        (prevMeta?.missingEmergencyPolls ?? 0) < 1
+          ? prevMeta.emergency
+          : aircraftEmergency(observation),
+      missingEmergencyPolls:
+        observation.emergency === undefined
+          ? (prevMeta?.missingEmergencyPolls ?? 0) + 1
+          : 0,
       // OpenSky distinguishes the last position epoch from the last
       // transponder message. The fleet coast horizon uses this actual
       // contact time so a temporarily old position does not hard-freeze

src/layers/flights/records.test.mjs

@@ -106,3 +106,13 @@ test('ground transitions preserve last render height while a surface cell is col
   assert.equal(next.meta.renderAltitudeM, 1040);
   assert.equal(next.meta.wasAirborne, true);
 });
+
+test('civil emergency status follows the latest poll instead of sticking', () => {
+  const store = records();
+  const first = store.receive(observation({ squawk: '7700' }), view());
+  assert.equal(first.meta.squawk, '7700');
+  assert.equal(first.meta.emergency.kind, 'general');
+  const next = store.receive(observation({ squawk: '2000' }), view());
+  assert.equal(next.meta.squawk, '2000');
+  assert.equal(next.meta.emergency, null);
+});

src/layers/flights/rendering.js

@@ -3,6 +3,7 @@ import { cyberSonarBaseAlpha } from '../../cyberSonar.js';
 import { selectModelEligible } from '../../data/modelEligibility.js';
 import { civilAircraftModelSpec } from './modelSpec.js';
 import { CLASS_SCALE_2D } from '../../data/aircraftClass.js';
+import { isEmergency } from '../../data/aircraftEmergency.js';
 import { cockpitContactDotImage } from '../../data/cockpitContactDot.js';
 import { aircraftIcon, TRACKED_ICON_PX } from '../../data/aircraftIcons.js';
 import {
@@ -13,6 +14,7 @@ import {
 import { limitCourseStep, courseSlewCapDps } from '../../data/motionModel.js';
 import {
   MIL_TINT,
+  EMERGENCY_TINT,
   GROUND_SCALE,
   COCKPIT_CONTACT_SIZE_PX,
   COCKPIT_CIVILIAN_COLOR,
@@ -54,13 +56,34 @@ export function createRendering({
   const { applyAircraftBillboardTreatment, applyAircraftModelTreatment } =
     services.recession;
 
-  /** Fleet (untracked) billboard tint: amber for known-military, white otherwise.
+  /** True while this contact's latest poll broadcast an emergency code. */
+
+  function _isEmergency(icao24, info = flightState.records.data.get(icao24)) {
+    return isEmergency(info?.emergency);
+  }
+
+  /** Fleet (untracked) billboard tint: red while broadcasting an emergency,
+   *  amber for known-military, white otherwise.
    *  Ground traffic gets NO special tint (owner verdict 2026-07-03 field test). */
 
-  function _fleetBillboardColor(icao24) {
+  function _fleetBillboardColor(
+    icao24,
+    info = flightState.records.data.get(icao24),
+  ) {
+    if (_isEmergency(icao24, info)) return EMERGENCY_TINT;
     return isMilitaryIcao(icao24) ? MIL_TINT : Cesium.Color.WHITE;
   }
 
+  /** Cockpit far-contact dot tint: the emergency red outranks the category tint. */
+
+  function _cockpitContactColor(
+    icao24,
+    info = flightState.records.data.get(icao24),
+  ) {
+    if (_isEmergency(icao24, info)) return EMERGENCY_TINT;
+    return isMilitaryIcao(icao24) ? MIL_TINT : COCKPIT_CIVILIAN_COLOR;
+  }
+
   /** Fleet billboard scale: per-class scale, ×GROUND_SCALE while grounded. */
 
   function _fleetBillboardScale(icao24, klass) {
@@ -129,9 +152,7 @@ export function createRendering({
       bb.height = COCKPIT_CONTACT_SIZE_PX;
       bb.scale = limbScale;
       bb.scaleByDistance = _cockpitBillboardScaleByDistance();
-      bb.color = (
-        isMilitaryIcao(icao24) ? MIL_TINT : COCKPIT_CIVILIAN_COLOR
-      ).withAlpha(freshnessAlpha);
+      bb.color = _cockpitContactColor(icao24).withAlpha(freshnessAlpha);
       bb.rotation = 0;
       return;
     }
@@ -162,7 +183,7 @@ export function createRendering({
 
   function _modelColor(icao24) {
     if (icao24 === flightState._trackedIcao) return Cesium.Color.CYAN;
-    return isMilitaryIcao(icao24) ? MIL_TINT : Cesium.Color.WHITE;
+    return _fleetBillboardColor(icao24);
   }
 
   /** The FLEET's 3D-model regime: models3d enabled AND the camera zoomed in past the altitude
@@ -1009,10 +1030,8 @@ export function createRendering({
         flightState._cockpitNearContacts.has(icao24);
       const layerBaseColor =
         flightState._cockpitContactMode && !isCockpitNear
-          ? isMilitaryIcao(icao24)
-            ? MIL_TINT
-            : COCKPIT_CIVILIAN_COLOR
-          : _fleetBillboardColor(icao24);
+          ? _cockpitContactColor(icao24, info)
+          : _fleetBillboardColor(icao24, info);
       const baseColor = layerBaseColor;
       const treatment = applyAircraftBillboardTreatment({
         billboard: bb,

src/layers/gnss/index.js

@@ -0,0 +1,422 @@
+import * as Cesium from 'cesium';
+import {
+  GNSS_LEVEL_COLORS,
+  GNSS_MIN_AIRCRAFT,
+  GNSS_WINDOW_MS,
+  accumulateGnssObservations,
+  binGnssCells,
+  gnssProvenance,
+  pruneGnssObservations,
+} from './records.js';
+export * from './records.js';
+export { createAdsbGnssSource } from './source.js';
+
+/**
+ * GroundPrimitive allowPicking:false suppresses ids but still submits stencil
+ * commands in Cesium's pick pass, erasing picks of overlapping ground geometry.
+ * This fill participates only in rendering, so sibling polygons remain pickable.
+ */
+class GnssGroundFill extends Cesium.GroundPrimitive {
+  update(frameState) {
+    if (!frameState.passes.pick) super.update(frameState);
+  }
+}
+
+/** Low stays visible over land so coverage reads apart from no data. */
+const FILL_ALPHA = Object.freeze({ low: 0.3, medium: 0.42, high: 0.55 });
+const LEVEL_LABELS = Object.freeze({
+  low: 'Low-accuracy score < 2%',
+  medium: 'Low-accuracy score 2–10%',
+  high: 'Low-accuracy score > 10%',
+});
+
+/** Degrees at the centre of the current view, or null before the camera settles. */
+export function defaultGnssViewAnchor(viewer) {
+  const canvas = viewer?.scene?.canvas;
+  const ellipsoid = viewer?.scene?.globe?.ellipsoid;
+  // At globe scale the visible rectangle can be the whole world, whose
+  // midpoint is unrelated to the place under the screen centre.
+  const centre =
+    canvas?.clientWidth > 0 &&
+    canvas.clientHeight > 0 &&
+    viewer.camera?.pickEllipsoid?.(
+      new Cesium.Cartesian2(canvas.clientWidth / 2, canvas.clientHeight / 2),
+      ellipsoid,
+    );
+  const rectangle =
+    !centre && viewer?.camera?.computeViewRectangle?.(ellipsoid);
+  const carto = centre
+    ? (ellipsoid || Cesium.Ellipsoid.WGS84).cartesianToCartographic(centre)
+    : rectangle
+      ? Cesium.Rectangle.center(rectangle)
+      : viewer?.camera?.positionCartographic;
+  if (!carto) return null;
+  const latitude = Cesium.Math.toDegrees(carto.latitude);
+  const longitude = Cesium.Math.toDegrees(carto.longitude);
+  return Number.isFinite(latitude) && Number.isFinite(longitude)
+    ? { latitude, longitude }
+    : null;
+}
+
+/**
+ * Own one GNSS navigation-integrity display: rolling integrity observations
+ * around the views the user visits, binned into cells coloured by the
+ * gpsjam low-accuracy score. Share links retain token 3.
+ */
+export function createGnssIntegrityLayer({
+  source,
+  viewAnchor = defaultGnssViewAnchor,
+  now = () => Date.now(),
+  monotonicNow = () => performance.now(),
+  windowMs = GNSS_WINDOW_MS,
+} = {}) {
+  if (typeof source?.getSnapshot !== 'function')
+    throw new TypeError('GNSS integrity layer requires a snapshot source');
+  let _viewer = null;
+  let _primitives = null;
+  let _request = null;
+  let _enabled = false;
+  let _cells = [];
+  let _signature = null;
+  let _lastUpdate = null;
+  let _lastError = null;
+  let _stale = false;
+  let _manager = null;
+  let _cameraTimer = null;
+  let _backgroundRefresh = null;
+  let _lastQueryKey = null;
+  let _lastRequestAt = -Infinity;
+  let _removeCameraEnd = null;
+  let _removeCameraChanged = null;
+  let _coverage = null;
+  let _retryTimer = null;
+  let _retryAt = 0;
+  let _failureCount = 0;
+  const _observations = new Map();
+  const provenance = gnssProvenance({ windowMs });
+
+  const queryKey = (anchor) =>
+    anchor
+      ? `${Math.round(anchor.latitude)},${Math.round(anchor.longitude)}`
+      : null;
+
+  function scheduleCameraRefresh() {
+    if (!_enabled || !_primitives) return;
+    if (now() < _retryAt) return;
+    const key = queryKey(viewAnchor(_viewer));
+    if (!key || key === _lastQueryKey) return;
+    clearTimeout(_cameraTimer);
+    // Debounce drags and bound moving/follow cameras to at most 24 requests
+    // per minute. Nearby views share the proxy's whole-degree cache key.
+    _cameraTimer = setTimeout(
+      async () => {
+        _cameraTimer = null;
+        if (!_enabled || _backgroundRefresh || _request) return;
+        const key = queryKey(viewAnchor(_viewer));
+        if (!key || key === _lastQueryKey) return;
+        await refreshInBackground();
+      },
+      Math.max(600, 2500 - (monotonicNow() - _lastRequestAt)),
+    );
+  }
+
+  async function refreshInBackground() {
+    if (!_enabled || _backgroundRefresh) return;
+    const controller = new AbortController();
+    _backgroundRefresh = controller;
+    try {
+      if (_manager)
+        await _manager.refreshLayer(layer.id, { signal: controller.signal });
+      else await layer.update(undefined, { signal: controller.signal });
+    } finally {
+      if (_backgroundRefresh === controller) {
+        _backgroundRefresh = null;
+        scheduleCameraRefresh();
+        scheduleRetry();
+      }
+    }
+  }
+
+  function scheduleRetry() {
+    clearTimeout(_retryTimer);
+    _retryTimer = null;
+    if (!_enabled || !_retryAt) return;
+    // Long provider cooldowns keep their full deadline. Browser timers cannot
+    // exceed ~24 days, so wake in bounded chunks without fetching early.
+    _retryTimer = setTimeout(
+      () => {
+        _retryTimer = null;
+        void refreshInBackground();
+      },
+      Math.min(2147483647, Math.max(0, _retryAt - now())),
+    );
+    _retryTimer?.unref?.();
+  }
+
+  /** Age the store without new evidence, so expired cells leave the globe. */
+  function expire() {
+    pruneGnssObservations(_observations, now(), { windowMs });
+    _cells = binGnssCells(_observations);
+    render();
+  }
+
+  function render() {
+    // Only the id and band change what is drawn; counts alone do not.
+    const signature = JSON.stringify(
+      _cells.map(({ id, level }) => [id, level]),
+    );
+    if (signature === _signature) return;
+    _signature = signature;
+    _primitives.removeAll();
+    if (_cells.length) {
+      _primitives.add(
+        new GnssGroundFill({
+          geometryInstances: _cells.map(
+            (cell) =>
+              new Cesium.GeometryInstance({
+                id: `${layer.id}:${cell.id}`,
+                geometry: new Cesium.RectangleGeometry({
+                  rectangle: Cesium.Rectangle.fromDegrees(
+                    cell.west,
+                    cell.south,
+                    cell.east,
+                    cell.north,
+                  ),
+                  vertexFormat: Cesium.PerInstanceColorAppearance.VERTEX_FORMAT,
+                }),
+                attributes: {
+                  color: Cesium.ColorGeometryInstanceAttribute.fromColor(
+                    Cesium.Color.fromCssColorString(
+                      GNSS_LEVEL_COLORS[cell.level],
+                    ).withAlpha(FILL_ALPHA[cell.level]),
+                  ),
+                },
+              }),
+          ),
+          appearance: new Cesium.PerInstanceColorAppearance({
+            flat: true,
+            translucent: true,
+          }),
+          classificationType: Cesium.ClassificationType.BOTH,
+          allowPicking: false,
+          // Retain the compact rectangle descriptors for inspection, not Entity visualizers.
+          releaseGeometryInstances: false,
+        }),
+      );
+    }
+    _viewer?.scene?.requestRender?.();
+  }
+
+  const layer = {
+    id: 'gnss-integrity',
+    name: 'GNSS Integrity',
+    icon: '📡',
+    source: 'adsb.lol',
+    /** Where each part of the method comes from; see records.js. */
+    provenance,
+    updateInterval: 60000,
+
+    attachDataManager(manager) {
+      _manager = manager;
+    },
+
+    init(viewer) {
+      if (_viewer)
+        throw new Error('GNSS integrity layer is already initialized');
+      _viewer = viewer;
+      _primitives = new Cesium.PrimitiveCollection();
+      _primitives.id = layer.id;
+      _primitives.show = false;
+      viewer.scene.groundPrimitives.add(_primitives);
+      _removeCameraEnd = viewer.camera?.moveEnd?.addEventListener(
+        scheduleCameraRefresh,
+      );
+      _removeCameraChanged = viewer.camera?.changed?.addEventListener(
+        scheduleCameraRefresh,
+      );
+    },
+
+    enable() {
+      _enabled = true;
+      // Cells left from before a long disable must not reappear past the window.
+      if (_primitives) {
+        expire();
+        _primitives.show = true;
+      }
+    },
+
+    disable() {
+      clearTimeout(_cameraTimer);
+      _cameraTimer = null;
+      clearTimeout(_retryTimer);
+      _retryTimer = null;
+      _backgroundRefresh?.abort();
+      _backgroundRefresh = null;
+      _request?.abort();
+      _request = null;
+      _enabled = false;
+      if (_primitives) _primitives.show = false;
+    },
+
+    async update(_viewerArg, { signal } = {}) {
+      if (!_enabled || !_primitives || signal?.aborted) return false;
+      if (now() < _retryAt) {
+        expire();
+        scheduleRetry();
+        return true;
+      }
+      _retryAt = 0;
+      clearTimeout(_retryTimer);
+      _retryTimer = null;
+      const anchor = viewAnchor(_viewer);
+      // No anchor yet (camera still settling) is not a failure: returning
+      // false would make the manager reject the enable. The next interval
+      // retries; cells already drawn still age out of the window.
+      if (!anchor) {
+        expire();
+        return true;
+      }
+      _request?.abort();
+      const request = new AbortController();
+      _request = request;
+      const onAbort = () => request.abort(signal.reason);
+      signal?.addEventListener('abort', onAbort, { once: true });
+      _lastQueryKey = queryKey(anchor);
+      _lastRequestAt = monotonicNow();
+      _coverage = {
+        kind: 'regional',
+        latitude: Math.round(anchor.latitude),
+        longitude: Math.round(anchor.longitude),
+        radiusNm: 250,
+      };
+      let received = false;
+      try {
+        const snapshot = await source.getSnapshot(anchor, {
+          signal: request.signal,
+        });
+        if (request.signal.aborted || _request !== request || !_enabled)
+          return false;
+        received = true;
+        // Date the rows by when the proxy observed them: a cached or stale
+        // replay keeps its original age instead of restarting the window.
+        // The proxy reports that age, so client and server clocks never mix.
+        const at = now();
+        accumulateGnssObservations(_observations, snapshot.rows, at, {
+          windowMs,
+          observedAt: at - snapshot.ageMs,
+        });
+        _cells = binGnssCells(_observations);
+        render();
+        _stale = snapshot.stale === true;
+        _lastUpdate = at - snapshot.ageMs;
+        _lastError = null;
+        _retryAt = 0;
+        _failureCount = 0;
+        return true;
+      } catch (e) {
+        if (request.signal.aborted || _request !== request || !_enabled)
+          return false;
+        // A renderer/programming failure remains a real lifecycle failure.
+        // Only acquisition failures are kept enabled for recovery.
+        if (received) throw e;
+        console.warn('[Data:GNSS] Fetch error:', e);
+        _lastError = e?.message || 'GNSS integrity source unavailable';
+        // Keep the last cells only while their evidence is inside the window.
+        expire();
+        if (e?.retryable === false) return false;
+        _failureCount = Math.min(3, _failureCount + 1);
+        const delay =
+          Number.isFinite(e?.retryAfterMs) && e.retryAfterMs > 0
+            ? e.retryAfterMs
+            : Math.min(120000, 30000 * 2 ** (_failureCount - 1));
+        _retryAt = Math.max(
+          _retryAt,
+          Math.min(Number.MAX_VALUE, now() + delay),
+        );
+        // Enabling the display succeeded. Stats still report an unavailable
+        // or degraded feed; the manager keeps its normal refresh failure lane.
+        return true;
+      } finally {
+        signal?.removeEventListener('abort', onAbort);
+        if (_request === request) _request = null;
+        scheduleCameraRefresh();
+        scheduleRetry();
+      }
+    },
+
+    destroy(viewer = _viewer) {
+      layer.disable();
+      _removeCameraEnd?.();
+      _removeCameraChanged?.();
+      _removeCameraEnd = null;
+      _removeCameraChanged = null;
+      _observations.clear();
+      _cells = [];
+      _signature = null;
+      if (_primitives) {
+        viewer.scene.groundPrimitives.remove(_primitives);
+        _primitives = null;
+      }
+      _viewer = null;
+      _lastUpdate = null;
+      _lastError = null;
+      _stale = false;
+      _coverage = null;
+      _retryAt = 0;
+      _failureCount = 0;
+      _lastQueryKey = null;
+      _manager = null;
+    },
+
+    getRowControls() {
+      return {
+        chips: [],
+        info:
+          'Regional sample · 250 nm radius · cells from visited views over 30 min' +
+          (_lastError && _retryAt
+            ? ` · ${_lastError} · Retrying automatically${
+                _retryAt <= 8640000000000000
+                  ? ` at ${new Date(_retryAt).toISOString().slice(11, 19)} UTC`
+                  : ' after provider cooldown'
+              }`
+            : ''),
+        infoTitle:
+          'Updates automatically after pan or zoom and once a minute. The public feed covers a 250-nautical-mile circle around the view centre; zooming out does not make it a worldwide snapshot. Blank cells are outside sampled coverage or have insufficient observations.',
+        legend: ['high', 'medium', 'low'].map((level, index) => ({
+          label: LEVEL_LABELS[level],
+          color: GNSS_LEVEL_COLORS[level],
+          count: _cells.filter((cell) => cell.level === level).length,
+          ...(index === 0
+            ? {
+                blurb: `Low-accuracy score = 100 × max(0, bad − 1) / total: one aircraft is discounted, so this is not the raw share. Cells need ${GNSS_MIN_AIRCRAFT} aircraft over ${provenance.window.minutes} minutes. Navigation-integrity anomalies are not a detection of jamming or spoofing.`,
+              }
+            : {}),
+        })),
+      };
+    },
+
+    getStats() {
+      return {
+        count: _cells.length,
+        levels: Object.fromEntries(
+          ['low', 'medium', 'high'].map((level) => [
+            level,
+            _cells.filter((cell) => cell.level === level).length,
+          ]),
+        ),
+        lastUpdate: _lastUpdate,
+        error: _lastError,
+        retryInSec: _retryAt
+          ? Math.max(0, Math.ceil((_retryAt - now()) / 1000))
+          : null,
+        stale: _stale,
+        provenance,
+        coverage: _coverage,
+        // Load-bearing: without an explicit boolean, layerFeedState reads the
+        // adsb.lol source name as a flights fallback (src/data/feedState.js).
+        fallback: false,
+      };
+    },
+  };
+  return layer;
+}

src/layers/gnss/ownership.test.mjs

@@ -0,0 +1,700 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import * as Cesium from 'cesium';
+import { createGnssIntegrityLayer, defaultGnssViewAnchor } from './index.js';
+import { LayerLifecycle } from '../../data/lifecycle.js';
+import { layerFeedState } from '../../data/feedState.js';
+
+const row = (hex, lat, degraded) => ({
+  hex,
+  lat,
+  lon: 30.2,
+  nic: degraded ? 0 : 8,
+  nacp: degraded ? 0 : 10,
+  gpsLost: false,
+  degraded,
+});
+
+function harness(
+  getSnapshot,
+  {
+    anchor: initialAnchor = { latitude: 50, longitude: 30 },
+    initialize = true,
+  } = {},
+) {
+  let anchor = initialAnchor;
+  const sources = [];
+  const viewer = {
+    camera: { moveEnd: new Cesium.Event(), changed: new Cesium.Event() },
+    scene: {
+      globe: { show: true },
+      groundPrimitives: {
+        add(value) {
+          sources.push(value);
+        },
+        remove(value) {
+          sources.splice(sources.indexOf(value), 1);
+          value.destroy();
+        },
+      },
+    },
+  };
+  let clock = 1_000;
+  const anchors = [];
+  const layer = createGnssIntegrityLayer({
+    // The real source refuses an undated snapshot; stubs default to a fresh one.
+    source: {
+      async getSnapshot(...args) {
+        const snapshot = await getSnapshot(...args);
+        return { ageMs: 0, ...snapshot };
+      },
+    },
+    viewAnchor: () => {
+      anchors.push(anchor);
+      return anchor;
+    },
+    now: () => clock,
+    monotonicNow: () => clock,
+  });
+  if (initialize) layer.init(viewer);
+  return {
+    layer,
+    sources,
+    anchors,
+    viewer,
+    advance(ms) {
+      clock += ms;
+    },
+    now: () => clock,
+    setAnchor(value) {
+      anchor = value;
+    },
+  };
+}
+
+const MIN = 60_000;
+const threeHealthy = () => [
+  row('a1', 1.1, false),
+  row('a2', 1.2, false),
+  row('a3', 1.3, false),
+];
+
+const flush = () => new Promise((resolve) => setImmediate(resolve));
+
+test('a globe-wide rectangle uses the visible screen centre as the query anchor', () => {
+  const anchor = defaultGnssViewAnchor({
+    scene: {
+      canvas: { clientWidth: 1000, clientHeight: 800 },
+      globe: { ellipsoid: Cesium.Ellipsoid.WGS84 },
+    },
+    camera: {
+      pickEllipsoid(pixel) {
+        assert.deepEqual(pixel, new Cesium.Cartesian2(500, 400));
+        return Cesium.Cartesian3.fromDegrees(-97, 30);
+      },
+      computeViewRectangle: () => {
+        throw new Error('centre hit must not compute a rectangle');
+      },
+    },
+  });
+  assert.ok(Math.abs(anchor.latitude - 30) < 1e-8);
+  assert.ok(Math.abs(anchor.longitude + 97) < 1e-8);
+});
+
+test('pan and zoom refresh through the manager without toggling; nearby changes are coalesced', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout', 'setInterval'] });
+  let calls = 0;
+  const h = harness(
+    async () => {
+      calls++;
+      return { rows: threeHealthy() };
+    },
+    { initialize: false },
+  );
+  const manager = new LayerLifecycle(h.viewer);
+  manager.register(h.layer);
+  h.layer.attachDataManager(manager);
+  const changes = [];
+  manager.subscribe((change) => changes.push(change.type));
+  await manager.setEnabled(h.layer.id, true);
+  h.setAnchor({ latitude: 54, longitude: 19 });
+  h.viewer.camera.changed.raiseEvent();
+  h.setAnchor({ latitude: 55, longitude: 20 });
+  h.viewer.camera.moveEnd.raiseEvent();
+  h.advance(2500);
+  t.mock.timers.tick(2500);
+  await flush();
+  assert.equal(calls, 2, 'one initial read and one read for the latest view');
+  assert.deepEqual(h.anchors.at(-1), { latitude: 55, longitude: 20 });
+  assert.ok(changes.includes('refresh-transition'));
+  assert.ok(changes.includes('refresh'));
+  assert.equal(manager.isEnabled(h.layer.id), true);
+  assert.deepEqual(h.layer.getStats().coverage, {
+    kind: 'regional',
+    latitude: 55,
+    longitude: 20,
+    radiusNm: 250,
+  });
+  assert.match(h.layer.getRowControls().info, /Regional sample.*250 nm radius/);
+  h.setAnchor({ latitude: 55.1, longitude: 20.1 });
+  h.viewer.camera.changed.raiseEvent();
+  h.advance(5000);
+  t.mock.timers.tick(5000);
+  await flush();
+  assert.equal(calls, 2, 'nearby views reuse the same query region');
+  await manager.destroyAll();
+  assert.equal(h.viewer.camera.moveEnd.numberOfListeners, 0);
+  assert.equal(h.viewer.camera.changed.numberOfListeners, 0);
+});
+
+test('movement during a pending refresh follows up at the newest view; disable cancels queued work', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  const calls = [];
+  let resolvePending;
+  const h = harness((anchor) => {
+    calls.push(anchor);
+    if (calls.length === 2)
+      return new Promise((resolve) => {
+        resolvePending = resolve;
+      });
+    return { rows: threeHealthy() };
+  });
+  h.layer.enable();
+  await h.layer.update();
+  h.setAnchor({ latitude: 54, longitude: 19 });
+  h.viewer.camera.moveEnd.raiseEvent();
+  h.advance(2500);
+  t.mock.timers.tick(2500);
+  await flush();
+  h.setAnchor({ latitude: 35, longitude: 140 });
+  h.viewer.camera.changed.raiseEvent();
+  h.advance(2500);
+  t.mock.timers.tick(2500);
+  await flush();
+  assert.equal(calls.length, 2, 'only one camera request in flight');
+  resolvePending({ rows: threeHealthy() });
+  await flush();
+  h.advance(600);
+  t.mock.timers.tick(600);
+  await flush();
+  assert.equal(calls.length, 3);
+  assert.deepEqual(calls.at(-1), { latitude: 35, longitude: 140 });
+  h.setAnchor({ latitude: 10, longitude: 10 });
+  h.viewer.camera.moveEnd.raiseEvent();
+  h.layer.disable();
+  h.advance(5000);
+  t.mock.timers.tick(5000);
+  await flush();
+  assert.equal(calls.length, 3, 'disable drains the camera timer');
+  h.layer.destroy();
+});
+
+test('the layer requires a snapshot source and cannot be initialized twice', () => {
+  assert.throws(() => createGnssIntegrityLayer({}), TypeError);
+  const { layer } = harness(async () => ({ rows: [] }));
+  assert.throws(() => layer.init({ dataSources: { add() {} } }), /already/);
+});
+
+test('an enabled refresh bins the snapshot into coloured ground cells', async () => {
+  const { layer, sources, anchors } = harness(async (anchor, { signal }) => {
+    assert.deepEqual(anchor, { latitude: 50, longitude: 30 });
+    assert.ok(signal instanceof AbortSignal);
+    return {
+      rows: [
+        row('a1', 50.1, true),
+        row('a2', 50.1, true),
+        row('a3', 50.2, false),
+        row('a4', 50.3, false),
+        row('b1', 55.1, false),
+      ],
+      stale: false,
+    };
+  });
+  assert.equal(await layer.update(), false, 'disabled layers do not fetch');
+  assert.equal(anchors.length, 0);
+  layer.enable();
+  assert.equal(sources[0].show, true);
+  assert.equal(await layer.update(), true);
+  const entities = sources[0].get(0).geometryInstances;
+  assert.equal(entities.length, 1, 'the one-aircraft cell is withheld');
+  assert.equal(entities[0].id, 'gnss-integrity:280:420');
+  assert.ok(entities[0].geometry instanceof Cesium.RectangleGeometry);
+  assert.equal(sources[0].get(0).allowPicking, false);
+  const stats = layer.getStats();
+  assert.equal(stats.count, 1);
+  assert.equal(stats.error, null);
+  assert.equal(stats.fallback, false);
+  const { legend } = layer.getRowControls();
+  assert.deepEqual(
+    legend.map(({ count }) => count),
+    [1, 0, 0],
+  );
+  assert.match(legend[0].blurb, /not a detection/);
+  assert.match(legend[0].blurb, /need 3 aircraft/);
+});
+
+test('the visible layer leads with low navigation accuracy and exposes its provenance', async () => {
+  const { layer } = harness(async () => ({ rows: [], stale: false }));
+  assert.equal(
+    layer.id,
+    'gnss-integrity',
+    'the unpublished id describes the measured state',
+  );
+  assert.equal(layer.name, 'GNSS Integrity');
+  assert.doesNotMatch(layer.name, /interference|jamming/i);
+  const { legend } = layer.getRowControls();
+  assert.deepEqual(
+    legend.map(({ label }) => label),
+    [
+      'Low-accuracy score > 10%',
+      'Low-accuracy score 2–10%',
+      'Low-accuracy score < 2%',
+    ],
+  );
+  const { blurb } = legend[0];
+  assert.match(blurb, /one aircraft is discounted/);
+  assert.match(blurb, /not the raw share/);
+  assert.match(blurb, /not a detection/);
+  assert.equal(layer.provenance.classifier.id, 'gev-nic-nacp-v2');
+  assert.equal(layer.provenance.classifier.definedBy, 'GEV');
+  assert.equal(layer.provenance.classifier.validated, false);
+  assert.equal(layer.provenance.aggregation.source, 'https://gpsjam.org/faq');
+  assert.deepEqual(layer.provenance.window, {
+    minutes: 30,
+    scope: 'visited-view',
+    cellDeg: 0.5,
+    minAircraft: 3,
+    definedBy: 'GEV',
+  });
+  assert.equal(layer.provenance.interpretation.validated, false);
+  assert.equal(layer.getStats().provenance, layer.provenance);
+});
+
+test('a failed refresh keeps the last cells and reports the error', async () => {
+  let fail = false;
+  const { layer, sources } = harness(async () => {
+    if (fail) throw new Error('adsb.lol HTTP 502');
+    return {
+      rows: [
+        row('a1', 1.1, false),
+        row('a2', 1.2, false),
+        row('a3', 1.3, false),
+      ],
+      stale: true,
+    };
+  });
+  layer.enable();
+  await layer.update();
+  assert.equal(layer.getStats().stale, true);
+  fail = true;
+  assert.equal(await layer.update(), true);
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 1);
+  assert.equal(layer.getStats().error, 'adsb.lol HTTP 502');
+  assert.equal(layer.getStats().count, 1);
+});
+
+test('observations expire with the window, and disable aborts the request in flight', async () => {
+  let pending;
+  const { layer, sources, advance } = harness(
+    (anchor, { signal }) =>
+      new Promise((resolve, reject) => {
+        pending = { resolve };
+        signal.addEventListener('abort', () => reject(signal.reason));
+      }),
+  );
+  layer.enable();
+  let result = layer.update();
+  pending.resolve({
+    rows: [row('a1', 1.1, false), row('a2', 1.2, false), row('a3', 1.3, false)],
+  });
+  assert.equal(await result, true);
+  assert.equal(layer.getStats().count, 1);
+
+  advance(31 * 60_000);
+  result = layer.update();
+  pending.resolve({ rows: [] });
+  assert.equal(await result, true);
+  assert.equal(layer.getStats().count, 0);
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 0);
+
+  result = layer.update();
+  layer.disable();
+  assert.equal(await result, false);
+  assert.equal(sources[0].show, false);
+});
+
+test('no view anchor means no request, and destroy releases the data source', async () => {
+  let calls = 0;
+  const { layer, sources } = harness(
+    async () => {
+      calls += 1;
+      return { rows: [] };
+    },
+    { anchor: null },
+  );
+  layer.enable();
+  assert.equal(
+    await layer.update(),
+    true,
+    'a settling camera is not a failure',
+  );
+  assert.equal(calls, 0);
+  assert.equal(layer.getStats().error, null);
+  layer.destroy();
+  assert.equal(sources.length, 0);
+  assert.equal(layer.getStats().count, 0);
+});
+
+test('a replayed stale snapshot keeps its observation age and expires on time', async () => {
+  // The proxy keeps answering with the snapshot it observed at t=1000.
+  const { layer, sources, advance, now } = harness(async () => ({
+    rows: threeHealthy(),
+    ageMs: now() - 1_000,
+    stale: true,
+  }));
+  layer.enable();
+  assert.equal(await layer.update(), true);
+  assert.equal(layer.getStats().count, 1);
+  advance(29 * MIN);
+  assert.equal(await layer.update(), true);
+  assert.equal(layer.getStats().count, 1);
+  advance(2 * MIN);
+  assert.equal(
+    await layer.update(),
+    true,
+    'the replay is not an error, only no evidence',
+  );
+  assert.equal(
+    layer.getStats().count,
+    0,
+    'the replay did not restart the window',
+  );
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 0);
+});
+
+test('cells expire during prolonged fetch failures', async () => {
+  let fail = false;
+  const { layer, sources, advance } = harness(async () => {
+    if (fail) throw new Error('adsb.lol HTTP 502');
+    return { rows: threeHealthy() };
+  });
+  layer.enable();
+  await layer.update();
+  fail = true;
+  advance(20 * MIN);
+  assert.equal(await layer.update(), true);
+  assert.equal(layer.getStats().count, 1, 'still inside the window');
+  advance(11 * MIN);
+  assert.equal(await layer.update(), true);
+  assert.equal(layer.getStats().count, 0);
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 0);
+  assert.equal(layer.getStats().error, 'adsb.lol HTTP 502');
+});
+
+test('cells expire while no view anchor is available', async () => {
+  let calls = 0;
+  const { layer, sources, advance, setAnchor } = harness(async () => {
+    calls += 1;
+    return { rows: threeHealthy() };
+  });
+  layer.enable();
+  await layer.update();
+  setAnchor(null);
+  advance(20 * MIN);
+  assert.equal(await layer.update(), true);
+  assert.equal(layer.getStats().count, 1);
+  advance(11 * MIN);
+  assert.equal(await layer.update(), true);
+  assert.equal(calls, 1, 'no anchor means no request');
+  assert.equal(layer.getStats().count, 0);
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 0);
+  assert.equal(layer.getStats().error, null);
+});
+
+test('re-enabling after a long disable does not show cells past the window', async () => {
+  const { layer, sources, advance } = harness(async () => ({
+    rows: threeHealthy(),
+  }));
+  layer.enable();
+  await layer.update();
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 1);
+  layer.disable();
+  advance(31 * MIN);
+  layer.enable();
+  assert.equal(layer.getStats().count, 0);
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 0);
+});
+
+const threeCells = () => ({
+  rows: [row('a1', 50.1, true), row('a2', 50.1, true), row('a3', 50.2, false)],
+});
+
+test('an identical snapshot leaves the drawn entities untouched', async () => {
+  const { layer, sources } = harness(async () => threeCells());
+  layer.enable();
+  await layer.update();
+  const first = sources[0].get(0);
+  await layer.update();
+  assert.equal(sources[0].get(0)?.geometryInstances.length ?? 0, 1);
+  assert.equal(sources[0].get(0), first);
+});
+
+test('an initial feed failure stays enabled, reports unavailable, and recovers automatically', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout', 'setInterval'] });
+  let calls = 0;
+  const h = harness(
+    async () => {
+      calls++;
+      if (calls === 1) throw new Error('adsb.lol HTTP 502');
+      return { rows: threeHealthy() };
+    },
+    { initialize: false },
+  );
+  const manager = new LayerLifecycle(h.viewer);
+  manager.register(h.layer);
+  h.layer.attachDataManager(manager);
+  const changes = [];
+  manager.subscribe((c) => changes.push(c.type));
+  assert.equal(await manager.setEnabled(h.layer.id, true), true);
+  assert.equal(manager.isEnabled(h.layer.id), true);
+  assert.equal(layerFeedState(h.layer.getStats()), 'unavailable');
+  assert.equal(h.layer.getStats().retryInSec, 30);
+  assert.match(
+    h.layer.getRowControls().info,
+    /HTTP 502.*Retrying automatically at/,
+  );
+  assert.equal(changes.includes('visibility-failed'), false);
+  assert.equal(
+    await manager.refreshLayer(h.layer.id),
+    false,
+    'feed remains honestly unhealthy during cooldown',
+  );
+  assert.equal(calls, 1, 'a manual refresh cannot bypass cooldown');
+  h.advance(30000);
+  t.mock.timers.tick(30000);
+  await flush();
+  assert.equal(calls, 2);
+  assert.equal(manager.isEnabled(h.layer.id), true);
+  assert.equal(layerFeedState(h.layer.getStats()), 'nominal');
+  assert.equal(h.layer.getStats().count, 1);
+  assert.equal(h.layer.getStats().retryInSec, null);
+  assert.doesNotMatch(h.layer.getRowControls().info, /Retrying/);
+  await manager.destroyAll();
+});
+
+test('provider cooldown is preserved across movement and toggling; disable cancels retry work', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  let calls = 0;
+  const h = harness(async () => {
+    calls++;
+    if (calls === 1)
+      throw Object.assign(new Error('Rate limited (HTTP 429)'), {
+        retryAfterMs: 3600000,
+      });
+    return { rows: threeHealthy() };
+  });
+  h.layer.enable();
+  await h.layer.update();
+  h.setAnchor({ latitude: 10, longitude: 20 });
+  h.viewer.camera.moveEnd.raiseEvent();
+  h.advance(30000);
+  t.mock.timers.tick(30000);
+  await flush();
+  await h.layer.update();
+  assert.equal(calls, 1);
+  assert.equal(h.layer.getStats().retryInSec, 3570);
+  h.layer.disable();
+  h.advance(30000);
+  t.mock.timers.tick(30000);
+  await flush();
+  h.layer.enable();
+  await h.layer.update();
+  assert.equal(calls, 1, 'reenabling does not erase a provider deadline');
+  h.advance(3540000);
+  t.mock.timers.tick(3540000);
+  await flush();
+  assert.equal(calls, 2);
+  assert.deepEqual(h.anchors.at(-1), { latitude: 10, longitude: 20 });
+  h.layer.destroy();
+
+  const stopped = harness(async () => {
+    throw new Error('network unavailable');
+  });
+  stopped.layer.enable();
+  await stopped.layer.update();
+  stopped.layer.disable();
+  stopped.advance(30000);
+  t.mock.timers.tick(30000);
+  await flush();
+  assert.equal(stopped.anchors.length, 1, 'disabled layers do not retry');
+  stopped.layer.destroy();
+});
+
+test('repeated acquisition failures back off, while genuine non-retryable failures reject startup', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  let calls = 0;
+  const h = harness(async () => {
+    calls++;
+    throw new Error('network unavailable');
+  });
+  h.layer.enable();
+  await h.layer.update();
+  assert.equal(h.layer.getStats().retryInSec, 30);
+  h.advance(30000);
+  t.mock.timers.tick(30000);
+  await flush();
+  assert.equal(h.layer.getStats().retryInSec, 60);
+  h.advance(60000);
+  t.mock.timers.tick(60000);
+  await flush();
+  assert.equal(h.layer.getStats().retryInSec, 120);
+  assert.equal(calls, 3);
+  h.layer.destroy();
+  const fatal = harness(async () => {
+    throw Object.assign(new Error('invalid request (HTTP 400)'), {
+      retryable: false,
+    });
+  });
+  fatal.layer.enable();
+  assert.equal(await fatal.layer.update(), false);
+  assert.equal(fatal.layer.getStats().retryInSec, null);
+  fatal.layer.destroy();
+});
+
+test('GERMAN: stale snapshot keeps the source observation age in row stats', async () => {
+  const h = harness(async () => ({
+    rows: threeHealthy(),
+    ageMs: 120000,
+    stale: true,
+  }));
+  h.layer.enable();
+  await h.layer.update();
+  assert.equal(h.layer.getStats().lastUpdate, h.now() - 120000);
+  h.layer.destroy();
+});
+
+test('GERMAN: camera debounce and minimum request gap are pinned', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  let calls = 0;
+  const h = harness(async () => {
+    calls++;
+    return { rows: [] };
+  });
+  h.layer.enable();
+  await h.layer.update();
+  h.setAnchor({ latitude: 51, longitude: 31 });
+  h.viewer.camera.changed.raiseEvent();
+  h.advance(2499);
+  t.mock.timers.tick(2499);
+  await flush();
+  assert.equal(calls, 1);
+  h.advance(1);
+  t.mock.timers.tick(1);
+  await flush();
+  assert.equal(calls, 2);
+  h.advance(3000);
+  h.setAnchor({ latitude: 52, longitude: 32 });
+  h.viewer.camera.changed.raiseEvent();
+  h.advance(599);
+  t.mock.timers.tick(599);
+  await flush();
+  assert.equal(calls, 2);
+  h.advance(1);
+  t.mock.timers.tick(1);
+  await flush();
+  assert.equal(calls, 3);
+  h.layer.destroy();
+});
+
+test('camera movement during initial activation waits for acquisition before following up', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  const calls = [];
+  let resolve;
+  const h = harness((anchor) => {
+    calls.push(anchor);
+    return calls.length === 1
+      ? new Promise((r) => (resolve = r))
+      : Promise.resolve({ rows: threeHealthy() });
+  });
+  h.layer.enable();
+  const initial = h.layer.update();
+  h.setAnchor({ latitude: 51, longitude: 31 });
+  h.viewer.camera.changed.raiseEvent();
+  h.advance(2500);
+  t.mock.timers.tick(2500);
+  await flush();
+  assert.equal(calls.length, 1);
+  resolve({ rows: threeHealthy() });
+  assert.equal(await initial, true);
+  h.advance(600);
+  t.mock.timers.tick(600);
+  await flush();
+  assert.equal(calls.length, 2);
+  h.layer.destroy();
+});
+
+test('monotonic camera scheduling is unaffected by wall-clock rollback', async (t) => {
+  t.mock.timers.enable({ apis: ['setTimeout'] });
+  const h = harness(async () => ({ rows: [] }));
+  h.layer.destroy();
+  let wall = 1800000000000,
+    mono = 0,
+    anchor = { latitude: 50, longitude: 30 },
+    calls = 0;
+  const layer = createGnssIntegrityLayer({
+    source: {
+      getSnapshot: async () => {
+        calls++;
+        return { rows: [], ageMs: 0 };
+      },
+    },
+    viewAnchor: () => anchor,
+    now: () => wall,
+    monotonicNow: () => mono,
+  });
+  layer.init(h.viewer);
+  layer.enable();
+  await layer.update();
+  wall -= 3600000;
+  mono = 3000;
+  anchor = { latitude: 51, longitude: 31 };
+  h.viewer.camera.changed.raiseEvent();
+  mono += 600;
+  t.mock.timers.tick(600);
+  await flush();
+  assert.equal(calls, 2);
+  layer.destroy();
+});
+
+test('GNSS fill emits no pick-pass commands but keeps normal rendering', async (t) => {
+  const h = harness(async () => ({ rows: threeHealthy() }));
+  h.layer.enable();
+  await h.layer.update();
+  const fill = h.sources[0].get(0);
+  let updates = 0;
+  t.mock.method(Cesium.GroundPrimitive.prototype, 'update', () => updates++);
+  fill.update({ passes: { pick: true } });
+  assert.equal(updates, 0);
+  fill.update({ passes: { render: true, pick: false } });
+  assert.equal(updates, 1);
+  h.layer.destroy();
+  assert.equal(fill.isDestroyed(), true);
+});
+
+test('view anchor falls back to rectangle, then nadir, then no camera', () => {
+  assert.equal(defaultGnssViewAnchor({}), null);
+  const viewer = {
+    camera: {
+      computeViewRectangle: () => Cesium.Rectangle.fromDegrees(20, 40, 22, 42),
+    },
+  };
+  const rectangleAnchor = defaultGnssViewAnchor(viewer);
+  assert.ok(Math.abs(rectangleAnchor.latitude - 41) < 1e-10);
+  assert.ok(Math.abs(rectangleAnchor.longitude - 21) < 1e-10);
+  viewer.camera = {
+    positionCartographic: Cesium.Cartographic.fromDegrees(21, 41),
+  };
+  const nadirAnchor = defaultGnssViewAnchor(viewer);
+  assert.ok(Math.abs(nadirAnchor.latitude - 41) < 1e-10);
+  assert.ok(Math.abs(nadirAnchor.longitude - 21) < 1e-10);
+});

src/layers/gnss/records.js

@@ -0,0 +1,318 @@
+/**
+ * Low navigation accuracy reported by ADS-B aircraft, binned into cells.
+ *
+ * Aircraft broadcasting DO-260 version 1/2 ADS-B report how much they trust
+ * their own position: NIC (integrity containment radius) and NACp (position
+ * accuracy). A cluster of aircraft reporting low values in one area is a
+ * navigation-integrity anomaly. Jamming or spoofing is one common cause, so
+ * such clusters are a well-known public proxy for GNSS interference, but
+ * avionics faults and old transponders also report low values: suspected
+ * interference is a second, unvalidated interpretation, never the primary
+ * state.
+ *
+ * Three separately sourced parts make up the method (see `gnssProvenance`):
+ * - Per-aircraft classifier, defined by GEV: aircraft-reported NIC < 7
+ *   (except unknown NIC 0 with NACp >= 10) or NACp < 8 (borrowed
+ *   from the US 14 CFR 91.227(c) ADS-B Out performance minima, which are not
+ *   a published interference classifier) or the readsb/tar1090 `gpsOkBefore`
+ *   flag. gpsjam.org does not publish its per-aircraft threshold.
+ * - Cell aggregation: gpsjam.org's published formula and 2% / 10% bands.
+ * - Window: a GEV-defined rolling 30 minutes over the views the user visits.
+ */
+
+/** Position source can switch to MLAT after GPS loss; quality must remain aircraft-reported. */
+const QUALIFYING_TYPES = new Set(['adsb_icao', 'mlat']);
+/** Restrict to decoded DO-260A/B quality fields; readsb does not decode v3 quality as v3. */
+const QUALIFYING_VERSIONS = new Set([1, 2]);
+/** NIC below 7: containment radius of 0.2 NM or more (below the US 91.227 ADS-B Out minimum). GEV threshold. */
+export const GNSS_NIC_THRESHOLD = 7;
+/** NACp below 8: position uncertainty of 93 m or more (below the US 91.227 minimum). GEV threshold. */
+export const GNSS_NACP_THRESHOLD = 8;
+/** Positions older than this are not current evidence of the local sky. */
+const MAX_POSITION_AGE_S = 60;
+/** Cell edge in degrees: roughly 55 km north-south, similar in area to an H3 res-4 cell. */
+export const GNSS_CELL_DEG = 0.5;
+/** Hide sparse one- and two-aircraft cells; the aggregation separately discounts one bad report. */
+export const GNSS_MIN_AIRCRAFT = 3;
+/** Rolling window over which aircraft seen in a cell are counted. */
+export const GNSS_WINDOW_MS = 30 * 60_000;
+/** gpsjam.org band edges, in percent of aircraft (after discounting one). */
+export const GNSS_MEDIUM_PERCENT = 2;
+export const GNSS_HIGH_PERCENT = 10;
+
+/** Primary cell state: what the data shows (low navigation accuracy). */
+export const GNSS_ANOMALY_STATE = 'navigation-integrity-anomaly';
+export const GNSS_NOMINAL_STATE = 'nominal';
+/** Secondary, unvalidated reading of an anomaly cell. */
+export const GNSS_INTERPRETATION = 'suspected-gnss-interference';
+
+/** The per-aircraft rule; GEV-defined and not validated against known events. */
+export const GNSS_CLASSIFIER = Object.freeze({
+  id: 'gev-nic-nacp-v2',
+  rule: `gpsOkBefore set || aircraft-reported NACp < ${GNSS_NACP_THRESHOLD} || (aircraft-reported NIC < ${GNSS_NIC_THRESHOLD} && !(NIC === 0 && NACp >= 10))`,
+  basis: '14 CFR 91.227(c) ADS-B Out performance minima (US regulation)',
+  definedBy: 'GEV',
+  validated: false,
+});
+
+/**
+ * Machine-readable provenance of the cell output: which part of the method
+ * comes from where, and which parts are unvalidated.
+ *
+ * @param {{windowMs?: number}} [options] The window the layer actually uses.
+ */
+export function gnssProvenance({ windowMs = GNSS_WINDOW_MS } = {}) {
+  return Object.freeze({
+    classifier: GNSS_CLASSIFIER,
+    aggregation: Object.freeze({
+      id: 'gpsjam-cell-bands',
+      formula: '100 * max(0, bad - 1) / total',
+      bands: Object.freeze([GNSS_MEDIUM_PERCENT, GNSS_HIGH_PERCENT]),
+      source: 'https://gpsjam.org/faq',
+      definedBy: 'gpsjam.org',
+    }),
+    window: Object.freeze({
+      minutes: windowMs / 60_000,
+      scope: 'visited-view',
+      cellDeg: GNSS_CELL_DEG,
+      minAircraft: GNSS_MIN_AIRCRAFT,
+      definedBy: 'GEV',
+    }),
+    state: Object.freeze({
+      id: GNSS_ANOMALY_STATE,
+      meaning: 'low navigation accuracy reported by ADS-B aircraft',
+    }),
+    interpretation: Object.freeze({
+      id: GNSS_INTERPRETATION,
+      validated: false,
+      note: 'one possible cause of an anomaly cell; avionics faults also report low values',
+    }),
+  });
+}
+
+/** Provenance at the default window. */
+export const GNSS_PROVENANCE = gnssProvenance();
+
+const HEX_PATTERN = /^~?[0-9a-f]{6}$/;
+
+const finite = (value) => typeof value === 'number' && Number.isFinite(value);
+
+/**
+ * Reduce one adsb.lol / readsb `aircraft.json`-style payload to the integrity
+ * facts the layer needs. Returns null when the payload has no aircraft array.
+ *
+ * @param {{ac?: object[], now?: number}} payload - readsb-style snapshot.
+ * @returns {{hex: string, lat: number, lon: number, nic: number|null, nacp: number|null, gpsLost: boolean, degraded: boolean}[]|null}
+ */
+export function normalizeGnssAircraft(payload) {
+  if (!Array.isArray(payload?.ac)) return null;
+  const rows = [];
+  const seen = new Set();
+  for (const aircraft of payload.ac) {
+    if (!aircraft || typeof aircraft !== 'object') continue;
+    const hex = typeof aircraft.hex === 'string' ? aircraft.hex : '';
+    if (!HEX_PATTERN.test(hex) || seen.has(hex)) continue;
+    if (!QUALIFYING_TYPES.has(aircraft.type)) continue;
+    if (!QUALIFYING_VERSIONS.has(aircraft.version)) continue;
+    if (aircraft.alt_baro === 'ground' || !finite(aircraft.alt_baro)) continue;
+    let { lat, lon } = aircraft;
+    const derived = (field) =>
+      aircraft.tisb?.includes(field) || aircraft.mlat?.includes(field);
+    const nic = finite(aircraft.nic) && !derived('nic') ? aircraft.nic : null;
+    const nacp =
+      finite(aircraft.nac_p) && !derived('nac_p') ? aircraft.nac_p : null;
+    if (!finite(lat) || Math.abs(lat) > 90) continue;
+    if (!finite(lon) || Math.abs(lon) > 180) continue;
+    // Only a position confirmed within the last minute is current evidence; a
+    // missing, invalid or negative age confirms nothing.
+    const age = aircraft.seen_pos;
+    if (!finite(age) || age < 0 || age > MAX_POSITION_AGE_S) continue;
+    // readsb exposes the flag while GPS is lost (15 s–15 min after the
+    // last good position), and removes it on recovery. Locate that evidence
+    // at the last good GNSS position, rather than a later MLAT estimate.
+    const gpsLost = finite(aircraft.gpsOkBefore) && aircraft.gpsOkBefore > 0;
+    if (nic === null && nacp === null && !gpsLost) continue;
+    if (
+      gpsLost &&
+      finite(aircraft.gpsOkLat) &&
+      Math.abs(aircraft.gpsOkLat) <= 90 &&
+      finite(aircraft.gpsOkLon) &&
+      Math.abs(aircraft.gpsOkLon) <= 180
+    ) {
+      lat = aircraft.gpsOkLat;
+      lon = aircraft.gpsOkLon;
+    }
+    seen.add(hex);
+    rows.push({
+      hex,
+      lat,
+      lon,
+      nic,
+      nacp,
+      gpsLost,
+      degraded:
+        gpsLost ||
+        (nacp !== null && nacp < GNSS_NACP_THRESHOLD) ||
+        (nic !== null &&
+          nic < GNSS_NIC_THRESHOLD &&
+          !(nic === 0 && nacp !== null && nacp >= 10)),
+    });
+  }
+  return rows;
+}
+
+/** Stable key of the cell containing a position. */
+export function gnssCellKey(lat, lon, cellDeg = GNSS_CELL_DEG) {
+  const row = Math.floor((Math.min(lat, 89.999999) + 90) / cellDeg);
+  const col = Math.floor((Math.min(lon, 179.999999) + 180) / cellDeg);
+  return `${row}:${col}`;
+}
+
+/**
+ * Fold one snapshot into a rolling observation store. Each aircraft counts
+ * once per cell per window. Presence and degraded evidence age separately: a
+ * degraded report keeps the aircraft degraded in that cell for one window
+ * after the report itself, however many healthy reports follow, so an
+ * aircraft that loses GNSS mid-cell is not averaged away and a recovered one
+ * is not held degraded forever.
+ *
+ * Every row is dated by when the snapshot was observed, not when it arrived:
+ * replaying a cached or stale snapshot never makes its evidence younger, and
+ * a snapshot older than the window adds nothing.
+ *
+ * @param {Map<string, {cell: string, seenAt: number, degradedAt: number|null}>} store
+ * @param {ReturnType<typeof normalizeGnssAircraft>} rows
+ * @param {number} nowMs
+ * @param {{windowMs?: number, cellDeg?: number, observedAt?: number}} [options]
+ *   `observedAt` is the snapshot's observation time (defaults to `nowMs`;
+ *   a future time is clamped to `nowMs`, a non-finite one adds nothing).
+ * @returns {Map} The same store, pruned to the window.
+ */
+export function accumulateGnssObservations(
+  store,
+  rows,
+  nowMs,
+  {
+    windowMs = GNSS_WINDOW_MS,
+    cellDeg = GNSS_CELL_DEG,
+    observedAt = nowMs,
+  } = {},
+) {
+  const at = Number.isFinite(observedAt) ? Math.min(observedAt, nowMs) : NaN;
+  if (Number.isFinite(at) && nowMs - at <= windowMs) {
+    for (const row of rows || []) {
+      if (!Number.isFinite(row?.lat) || !Number.isFinite(row?.lon)) continue;
+      const cell = gnssCellKey(row.lat, row.lon, cellDeg);
+      const key = `${row.hex}|${cell}`;
+      const previous = store.get(key);
+      const previousDegradedAt = previous?.degradedAt ?? null;
+      store.set(key, {
+        cell,
+        seenAt: Math.max(previous?.seenAt ?? at, at),
+        degradedAt: row.degraded
+          ? Math.max(previousDegradedAt ?? at, at)
+          : previousDegradedAt,
+      });
+    }
+  }
+  return pruneGnssObservations(store, nowMs, { windowMs });
+}
+
+/**
+ * Drop observations older than the window and degraded evidence older than
+ * the window, without adding anything. Used when no fresh snapshot arrives.
+ *
+ * @param {Map<string, {cell: string, seenAt: number, degradedAt: number|null}>} store
+ * @param {number} nowMs
+ * @param {{windowMs?: number}} [options]
+ * @returns {Map} The same store.
+ */
+export function pruneGnssObservations(
+  store,
+  nowMs,
+  { windowMs = GNSS_WINDOW_MS } = {},
+) {
+  for (const [key, entry] of store) {
+    if (nowMs - entry.seenAt > windowMs) store.delete(key);
+    else if (entry.degradedAt != null && nowMs - entry.degradedAt > windowMs)
+      store.set(key, { ...entry, degradedAt: null });
+  }
+  return store;
+}
+
+/**
+ * Navigation-integrity level of a cell, using gpsjam.org's published cell
+ * formula and bands: the first degraded aircraft is discounted to limit false
+ * positives, then under 2% is low, 2–10% medium and over 10% high. Medium and
+ * high cells are navigation-integrity anomalies.
+ */
+export function gnssIntegrityLevel(total, degraded) {
+  const percent = total > 0 ? (100 * Math.max(0, degraded - 1)) / total : 0;
+  const level =
+    percent > GNSS_HIGH_PERCENT
+      ? 'high'
+      : percent >= GNSS_MEDIUM_PERCENT
+        ? 'medium'
+        : 'low';
+  const anomaly = level !== 'low';
+  return {
+    percent,
+    level,
+    state: anomaly ? GNSS_ANOMALY_STATE : GNSS_NOMINAL_STATE,
+    interpretation: anomaly ? GNSS_INTERPRETATION : null,
+  };
+}
+
+/**
+ * Aggregate the observation store into displayable cells. Expects a store
+ * already pruned to the window by `accumulateGnssObservations` or
+ * `pruneGnssObservations`.
+ *
+ * @returns {{id: string, south: number, west: number, north: number, east: number, lat: number, lon: number, aircraft: number, degraded: number, percentDegraded: number, level: 'low'|'medium'|'high', state: string, interpretation: string|null}[]}
+ */
+export function binGnssCells(
+  store,
+  { cellDeg = GNSS_CELL_DEG, minAircraft = GNSS_MIN_AIRCRAFT } = {},
+) {
+  const tallies = new Map();
+  for (const { cell, degradedAt } of store.values()) {
+    const tally = tallies.get(cell) || { aircraft: 0, degraded: 0 };
+    tally.aircraft += 1;
+    if (degradedAt != null) tally.degraded += 1;
+    tallies.set(cell, tally);
+  }
+  const cells = [];
+  for (const [id, { aircraft, degraded }] of tallies) {
+    if (aircraft < minAircraft) continue;
+    const [row, col] = id.split(':').map(Number);
+    const south = row * cellDeg - 90;
+    const west = col * cellDeg - 180;
+    const { percent, level, state, interpretation } = gnssIntegrityLevel(
+      aircraft,
+      degraded,
+    );
+    cells.push({
+      id,
+      south,
+      west,
+      north: south + cellDeg,
+      east: west + cellDeg,
+      lat: south + cellDeg / 2,
+      lon: west + cellDeg / 2,
+      aircraft,
+      degraded,
+      percentDegraded: Math.round(percent * 10) / 10,
+      level,
+      state,
+      interpretation,
+    });
+  }
+  return cells.sort((a, b) => a.id.localeCompare(b.id));
+}
+
+/** Legend colors: gpsjam's green / amber / red convention. */
+export const GNSS_LEVEL_COLORS = Object.freeze({
+  low: '#3fb950',
+  medium: '#e3b341',
+  high: '#f85149',
+});

src/layers/gnss/records.test.mjs

@@ -0,0 +1,491 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  accumulateGnssObservations,
+  binGnssCells,
+  GNSS_CLASSIFIER,
+  GNSS_PROVENANCE,
+  GNSS_WINDOW_MS,
+  gnssCellKey,
+  gnssIntegrityLevel,
+  gnssProvenance,
+  normalizeGnssAircraft,
+  pruneGnssObservations,
+} from './records.js';
+
+const aircraft = (overrides = {}) => ({
+  hex: '4ca7b5',
+  type: 'adsb_icao',
+  version: 2,
+  alt_baro: 36000,
+  lat: 50.1,
+  lon: 19.9,
+  nic: 8,
+  nac_p: 10,
+  seen_pos: 1.2,
+  ...overrides,
+});
+
+test('normalization keeps airborne decoded ADS-B v1/v2 quality with current positions', () => {
+  const rows = normalizeGnssAircraft({
+    ac: [
+      aircraft(),
+      aircraft({
+        hex: '000001',
+        type: 'mlat',
+        nic: undefined,
+        nac_p: undefined,
+      }),
+      aircraft({ hex: '000002', type: 'tisb_icao' }),
+      aircraft({ hex: '000003', version: 0 }),
+      aircraft({ hex: '000004', alt_baro: 'ground' }),
+      aircraft({ hex: '000005', seen_pos: 120 }),
+      aircraft({ hex: '000006', nic: undefined, nac_p: undefined }),
+      aircraft({ hex: '000007', lat: 95 }),
+      aircraft({ hex: '000008', version: undefined }),
+      // Only DO-260A/B (versions 1 and 2) define NIC and NACp.
+      aircraft({ hex: '000009', version: 3 }),
+      aircraft({ hex: '00000a', version: '2' }),
+      aircraft({ hex: '00000b', version: 1.5 }),
+      // A position is current only when its age is known, finite and 0..60 s.
+      aircraft({ hex: '00000c', seen_pos: undefined }),
+      aircraft({ hex: '00000d', seen_pos: null }),
+      aircraft({ hex: '00000e', seen_pos: -0.5 }),
+      aircraft({ hex: '00000f', seen_pos: '1.2' }),
+      aircraft({ hex: '000010', seen_pos: Number.NaN }),
+      aircraft({ hex: '000011', seen_pos: 60.1 }),
+      aircraft({ hex: 'not-hex' }),
+      aircraft(),
+      // A non-ICAO (`~`) address still self-reports over 1090ES ADS-B.
+      aircraft({ hex: '~a1b2c3' }),
+      // Version 1, and both ends of the position-age range, qualify.
+      aircraft({ hex: 'b00001', version: 1, seen_pos: 0 }),
+      aircraft({ hex: 'b00002', seen_pos: 60 }),
+      null,
+    ],
+  });
+  assert.deepEqual(rows, [
+    {
+      hex: '4ca7b5',
+      lat: 50.1,
+      lon: 19.9,
+      nic: 8,
+      nacp: 10,
+      gpsLost: false,
+      degraded: false,
+    },
+    {
+      hex: '~a1b2c3',
+      lat: 50.1,
+      lon: 19.9,
+      nic: 8,
+      nacp: 10,
+      gpsLost: false,
+      degraded: false,
+    },
+    ...['b00001', 'b00002'].map((hex) => ({
+      hex,
+      lat: 50.1,
+      lon: 19.9,
+      nic: 8,
+      nacp: 10,
+      gpsLost: false,
+      degraded: false,
+    })),
+  ]);
+  assert.equal(normalizeGnssAircraft({}), null);
+  assert.equal(normalizeGnssAircraft(null), null);
+});
+
+test('low NIC, low NACp or a readsb GPS-loss flag each mark an aircraft degraded', () => {
+  const rows = normalizeGnssAircraft({
+    ac: [
+      aircraft({ hex: 'a00001', nic: 6 }),
+      aircraft({ hex: 'a00002', nac_p: 7 }),
+      aircraft({ hex: 'a00003', gpsOkBefore: 1790690000.1 }),
+      aircraft({ hex: 'a00004', nic: 7, nac_p: 8 }),
+    ],
+  });
+  assert.deepEqual(
+    rows.map(({ hex, degraded, gpsLost }) => [hex, degraded, gpsLost]),
+    [
+      ['a00001', true, false],
+      ['a00002', true, false],
+      ['a00003', true, true],
+      ['a00004', false, false],
+    ],
+  );
+});
+
+test('cell keys are stable half-degree bins, clamped at the poles and antimeridian', () => {
+  assert.equal(gnssCellKey(50.1, 19.9), gnssCellKey(50.4, 19.6));
+  assert.notEqual(gnssCellKey(50.1, 19.9), gnssCellKey(50.6, 19.9));
+  assert.equal(gnssCellKey(90, 180), gnssCellKey(89.9, 179.9));
+  assert.equal(gnssCellKey(-90, -180), '0:0');
+  // Just south-west of the origin falls in the last cell before 0°, not cell 0.
+  assert.equal(gnssCellKey(-0.1, -0.1), '179:359');
+});
+
+test('integrity level follows the gpsjam.org published cell formula and bands', () => {
+  const nominal = {
+    percent: 0,
+    level: 'low',
+    state: 'nominal',
+    interpretation: null,
+  };
+  assert.deepEqual(gnssIntegrityLevel(10, 0), nominal);
+  // One degraded aircraft is always discounted.
+  assert.deepEqual(gnssIntegrityLevel(10, 1), nominal);
+  assert.equal(gnssIntegrityLevel(50, 2).level, 'medium');
+  assert.equal(gnssIntegrityLevel(10, 2).level, 'medium');
+  assert.equal(gnssIntegrityLevel(10, 3).level, 'high');
+  assert.equal(gnssIntegrityLevel(0, 0).level, 'low');
+});
+
+test('the primary state is a navigation-integrity anomaly; interference is only the secondary reading', () => {
+  for (const [total, bad] of [
+    [50, 2],
+    [10, 3],
+  ]) {
+    const { state, interpretation } = gnssIntegrityLevel(total, bad);
+    assert.equal(state, 'navigation-integrity-anomaly');
+    assert.equal(interpretation, 'suspected-gnss-interference');
+  }
+  const store = new Map();
+  accumulateGnssObservations(
+    store,
+    [
+      { hex: 'h1', lat: 10.1, lon: 10.1, degraded: true },
+      { hex: 'h2', lat: 10.2, lon: 10.2, degraded: true },
+      { hex: 'h3', lat: 10.3, lon: 10.3, degraded: false },
+    ],
+    0,
+  );
+  const [cell] = binGnssCells(store);
+  assert.equal(cell.level, 'high');
+  assert.equal(cell.state, 'navigation-integrity-anomaly');
+  assert.equal(cell.interpretation, 'suspected-gnss-interference');
+  for (const key of Object.keys(cell))
+    assert.doesNotMatch(key, /interference|jamming|spoof/i);
+});
+
+test('provenance separates the GEV classifier from the gpsjam aggregation and the GEV window', () => {
+  assert.deepEqual(GNSS_PROVENANCE.classifier, {
+    id: 'gev-nic-nacp-v2',
+    rule: 'gpsOkBefore set || aircraft-reported NACp < 8 || (aircraft-reported NIC < 7 && !(NIC === 0 && NACp >= 10))',
+    basis: '14 CFR 91.227(c) ADS-B Out performance minima (US regulation)',
+    definedBy: 'GEV',
+    validated: false,
+  });
+  assert.equal(GNSS_PROVENANCE.classifier, GNSS_CLASSIFIER);
+  assert.deepEqual(GNSS_PROVENANCE.aggregation, {
+    id: 'gpsjam-cell-bands',
+    formula: '100 * max(0, bad - 1) / total',
+    bands: [2, 10],
+    source: 'https://gpsjam.org/faq',
+    definedBy: 'gpsjam.org',
+  });
+  assert.deepEqual(GNSS_PROVENANCE.window, {
+    minutes: 30,
+    scope: 'visited-view',
+    cellDeg: 0.5,
+    minAircraft: 3,
+    definedBy: 'GEV',
+  });
+  assert.equal(GNSS_PROVENANCE.state.id, 'navigation-integrity-anomaly');
+  assert.equal(
+    GNSS_PROVENANCE.interpretation.id,
+    'suspected-gnss-interference',
+  );
+  assert.equal(GNSS_PROVENANCE.interpretation.validated, false);
+  assert.ok(Object.isFrozen(GNSS_PROVENANCE));
+  assert.ok(Object.isFrozen(GNSS_PROVENANCE.aggregation.bands));
+  // The bands in provenance are the ones the level function applies.
+  const [medium, high] = GNSS_PROVENANCE.aggregation.bands;
+  assert.equal(gnssIntegrityLevel(100, 1 + medium).level, 'medium');
+  assert.equal(gnssIntegrityLevel(100, 1 + high).level, 'medium');
+  assert.equal(gnssIntegrityLevel(100, 2 + high).level, 'high');
+  assert.equal(gnssProvenance({ windowMs: 10 * 60_000 }).window.minutes, 10);
+});
+
+test('observations count each aircraft once per cell and expire after the window', () => {
+  const store = new Map();
+  const at = (lat, hex, degraded) => ({ hex, lat, lon: 20.1, degraded });
+  accumulateGnssObservations(
+    store,
+    [at(50.1, 'a1', true), at(50.2, 'a2', false), at(50.3, 'a3', false)],
+    0,
+    { windowMs: 1000 },
+  );
+  // a1 recovers inside the same cell: it stays degraded for the window.
+  accumulateGnssObservations(store, [at(50.2, 'a1', false)], 500, {
+    windowMs: 1000,
+  });
+  let [cell] = binGnssCells(store);
+  assert.equal(cell.aircraft, 3);
+  assert.equal(cell.degraded, 1);
+  assert.equal(cell.level, 'low');
+  assert.deepEqual(
+    [cell.south, cell.west, cell.north, cell.east],
+    [50, 20, 50.5, 20.5],
+  );
+
+  accumulateGnssObservations(store, [], 1200, { windowMs: 1000 });
+  assert.equal(store.size, 1);
+  assert.deepEqual(binGnssCells(store), []);
+});
+
+const MIN = 60_000;
+const report = (hex, degraded, lat = 50.1) => ({
+  hex,
+  lat,
+  lon: 20.1,
+  degraded,
+});
+const entry = (store, hex) =>
+  [...store].find(([key]) => key.startsWith(`${hex}|`))?.[1];
+
+test('degraded evidence expires one window after the degraded report, despite continuing healthy reports', () => {
+  const store = new Map();
+  accumulateGnssObservations(store, [report('a1', true)], 0);
+  // a1 keeps reporting healthy every minute in the same cell.
+  for (let minute = 1; minute <= 30; minute += 1)
+    accumulateGnssObservations(store, [report('a1', false)], minute * MIN);
+  assert.equal(entry(store, 'a1').seenAt, 30 * MIN);
+  assert.equal(
+    entry(store, 'a1').degradedAt,
+    0,
+    'healthy reports do not refresh the degraded evidence',
+  );
+  accumulateGnssObservations(store, [report('a1', false)], 31 * MIN);
+  assert.deepEqual(entry(store, 'a1'), {
+    cell: gnssCellKey(50.1, 20.1),
+    seenAt: 31 * MIN,
+    degradedAt: null,
+  });
+  // A new degraded report starts its own window.
+  accumulateGnssObservations(store, [report('a1', true)], 32 * MIN);
+  assert.equal(entry(store, 'a1').degradedAt, 32 * MIN);
+  accumulateGnssObservations(store, [report('a1', false)], 40 * MIN);
+  assert.equal(entry(store, 'a1').degradedAt, 32 * MIN);
+});
+
+test('a degraded cell turns healthy once its degraded evidence is older than the window', () => {
+  const store = new Map();
+  const healthy = [report('a2', false), report('a3', false)];
+  accumulateGnssObservations(
+    store,
+    [report('a1', true), report('b1', true), ...healthy],
+    0,
+  );
+  assert.equal(binGnssCells(store)[0].level, 'high');
+  for (let minute = 10; minute <= 30; minute += 10)
+    accumulateGnssObservations(
+      store,
+      [report('a1', false), report('b1', false), ...healthy],
+      minute * MIN,
+    );
+  assert.equal(binGnssCells(store)[0].degraded, 2);
+  accumulateGnssObservations(
+    store,
+    [report('a1', false), report('b1', false), ...healthy],
+    31 * MIN,
+  );
+  const [cell] = binGnssCells(store);
+  assert.equal(cell.aircraft, 4);
+  assert.equal(cell.degraded, 0);
+  assert.equal(cell.level, 'low');
+});
+
+test('an aircraft returning after the window starts fresh', () => {
+  const store = new Map();
+  accumulateGnssObservations(store, [report('a1', true)], 0);
+  // a1 leaves; nothing is heard from it for longer than the window.
+  accumulateGnssObservations(store, [], 31 * MIN);
+  assert.equal(store.size, 0);
+  accumulateGnssObservations(store, [report('a1', false)], 32 * MIN);
+  assert.deepEqual(entry(store, 'a1'), {
+    cell: gnssCellKey(50.1, 20.1),
+    seenAt: 32 * MIN,
+    degradedAt: null,
+  });
+  // Returning degraded dates the evidence from the new report.
+  const again = new Map();
+  accumulateGnssObservations(again, [report('a9', true)], 0);
+  accumulateGnssObservations(again, [], 31 * MIN);
+  accumulateGnssObservations(again, [report('a9', true)], 33 * MIN);
+  assert.equal(entry(again, 'a9').degradedAt, 33 * MIN);
+});
+
+test('an aircraft heard healthy right after the window drops its stale degraded evidence', () => {
+  // No prune runs in between: the old entry is still in the store when the
+  // healthy report arrives, so the new report alone must not carry it over.
+  const store = new Map();
+  accumulateGnssObservations(store, [report('a1', true)], 0);
+  accumulateGnssObservations(store, [report('a1', false)], 31 * MIN);
+  assert.deepEqual(entry(store, 'a1'), {
+    cell: gnssCellKey(50.1, 20.1),
+    seenAt: 31 * MIN,
+    degradedAt: null,
+  });
+  // Exactly one window after the degraded report it still counts.
+  const edge = new Map();
+  accumulateGnssObservations(edge, [report('a1', true)], 0);
+  accumulateGnssObservations(edge, [report('a1', false)], 30 * MIN);
+  assert.equal(entry(edge, 'a1').degradedAt, 0);
+});
+
+test('rows are dated by the snapshot observation time, so a replay never restarts the window', () => {
+  const store = new Map();
+  const snapshot = [report('a1', true), report('a2', false)];
+  accumulateGnssObservations(store, snapshot, 0, { observedAt: 0 });
+  // The same snapshot replayed (cached or stale) 29 minutes later.
+  accumulateGnssObservations(store, snapshot, 29 * MIN, { observedAt: 0 });
+  assert.equal(entry(store, 'a1').seenAt, 0);
+  assert.equal(entry(store, 'a1').degradedAt, 0);
+  accumulateGnssObservations(store, snapshot, 31 * MIN, { observedAt: 0 });
+  assert.equal(store.size, 0, 'a replay older than the window adds nothing');
+
+  // An older replay never moves an entry's age backwards either.
+  accumulateGnssObservations(store, snapshot, 40 * MIN);
+  accumulateGnssObservations(store, [report('a2', true)], 41 * MIN, {
+    observedAt: 35 * MIN,
+  });
+  assert.equal(entry(store, 'a2').seenAt, 40 * MIN);
+  assert.equal(entry(store, 'a2').degradedAt, 35 * MIN);
+
+  // A future time is clamped to now; an undated snapshot adds nothing.
+  accumulateGnssObservations(store, [report('f1', true)], 50 * MIN, {
+    observedAt: 99 * MIN,
+  });
+  assert.equal(entry(store, 'f1').seenAt, 50 * MIN);
+  for (const observedAt of [null, Number.NaN])
+    accumulateGnssObservations(store, [report('u1', true)], 50 * MIN, {
+      observedAt,
+    });
+  assert.equal(entry(store, 'u1'), undefined);
+});
+
+test('pruning without new rows drops expired observations and expired degraded evidence', () => {
+  const store = new Map();
+  accumulateGnssObservations(store, [report('a1', true)], 0);
+  accumulateGnssObservations(store, [report('a1', false)], 20 * MIN);
+  accumulateGnssObservations(store, [report('a2', false)], 0);
+  assert.equal(pruneGnssObservations(store, 31 * MIN), store);
+  assert.deepEqual(
+    [...store.keys()].map((key) => key.split('|')[0]),
+    ['a1'],
+  );
+  assert.equal(entry(store, 'a1').degradedAt, null);
+  pruneGnssObservations(store, 51 * MIN);
+  assert.equal(store.size, 0);
+  assert.equal(GNSS_WINDOW_MS, 30 * MIN);
+});
+
+test('rows without finite coordinates never key a cell', () => {
+  const store = new Map();
+  accumulateGnssObservations(
+    store,
+    [
+      { hex: 'n1', lat: Number.NaN, lon: 10.1, degraded: true },
+      { hex: 'n2', lat: 10.1, lon: '10.1', degraded: true },
+      null,
+    ],
+    0,
+  );
+  assert.equal(store.size, 0);
+});
+
+test('cells below the minimum aircraft count are withheld', () => {
+  const store = new Map();
+  accumulateGnssObservations(
+    store,
+    [
+      { hex: 'b1', lat: 10.1, lon: 10.1, degraded: true },
+      { hex: 'b2', lat: 10.2, lon: 10.2, degraded: true },
+    ],
+    0,
+  );
+  assert.deepEqual(binGnssCells(store), []);
+  const [cell] = binGnssCells(store, { minAircraft: 2 });
+  assert.equal(cell.level, 'high');
+  assert.equal(cell.percentDegraded, 50);
+});
+
+test('MLAT GPS-loss evidence uses the last good GNSS location and ignores MLAT NIC', () => {
+  const [row] = normalizeGnssAircraft({
+    ac: [
+      aircraft({
+        type: 'mlat',
+        nac_p: 0,
+        nic: 0,
+        mlat: ['lat', 'lon', 'nic'],
+        gpsOkBefore: 1800000000,
+        gpsOkLat: 54.2,
+        gpsOkLon: 19.3,
+      }),
+    ],
+  });
+  assert.ok(row);
+  assert.equal(row.lat, 54.2);
+  assert.equal(row.lon, 19.3);
+  assert.equal(row.nic, null);
+  assert.equal(row.degraded, true);
+  const [healthy] = normalizeGnssAircraft({
+    ac: [aircraft({ type: 'mlat', nic: 0, mlat: ['nic'] })],
+  });
+  assert.equal(healthy.degraded, false);
+});
+
+test('TIS-B accuracy fields and unknown containment do not manufacture anomalies', () => {
+  const rows = normalizeGnssAircraft({
+    ac: [
+      aircraft({ hex: 'a00001', nac_p: 0, tisb: ['nac_p'] }),
+      aircraft({ hex: 'a00002', nic: 0, tisb: ['nic'] }),
+      aircraft({ hex: 'a00003', nic: 0, nac_p: 10 }),
+      aircraft({ hex: 'a00004', nic: 0, nac_p: 8 }),
+      aircraft({ hex: 'a00005', nic: 6, nac_p: 10 }),
+    ],
+  });
+  assert.deepEqual(
+    rows.map((r) => r.degraded),
+    [false, false, false, true, true],
+  );
+});
+
+// Quality-field subsets captured from public adsb.lol US point responses on
+// 2026-10-14 (34,-118 and 41,-73, radius 250 nm), ODbL 1.0 / adsb.lol contributors.
+// Only field provenance is reused; the airborne ADS-B envelopes are synthetic.
+test('public US quality-field fixtures do not turn rebroadcast accuracy into own accuracy', () => {
+  const tisbQuality = {
+    nic: 0,
+    nac_p: 0,
+    tisb: [
+      'altitude',
+      'alt_baro',
+      'gs',
+      'track',
+      'geom_rate',
+      'lat',
+      'lon',
+      'nic',
+      'rc',
+      'nac_p',
+      'nac_v',
+      'sil',
+      'sil_type',
+    ],
+    mlat: [],
+  };
+  assert.deepEqual(normalizeGnssAircraft({ ac: [aircraft(tisbQuality)] }), []);
+  const unknownContainment = {
+    nic: 0,
+    nac_p: 10,
+    tisb: ['callsign'],
+    mlat: [],
+  };
+  assert.equal(
+    normalizeGnssAircraft({ ac: [aircraft(unknownContainment)] })[0].degraded,
+    false,
+  );
+});

src/layers/gnss/source.js

@@ -0,0 +1,76 @@
+import { readResponseJsonCapped } from '../../sources/httpBody.js';
+
+function retryDelay(raw, nowMs) {
+  if (!raw) return null;
+  const seconds = Number(raw);
+  const ms = seconds * 1000;
+  if (Number.isFinite(ms) && seconds > 0)
+    return Math.min(3600000, Math.max(5000, ms));
+  const at = Date.parse(raw);
+  return Number.isFinite(at) && at > nowMs
+    ? Math.min(3600000, Math.max(5000, at - nowMs))
+    : null;
+}
+
+/** Request integrity facts around a view anchor through the same-origin adsb.lol proxy. */
+export function createAdsbGnssSource({
+  fetchImpl = (...args) => globalThis.fetch(...args),
+  now = () => Date.now(),
+} = {}) {
+  return {
+    async getSnapshot({ latitude, longitude } = {}, { signal } = {}) {
+      signal?.throwIfAborted();
+      if (!Number.isFinite(latitude) || !Number.isFinite(longitude))
+        throw new Error('GNSS snapshot needs a view anchor');
+      const params = new URLSearchParams({
+        lat: String(Math.round(latitude)),
+        lon: String(Math.round(longitude)),
+      });
+      const response = await fetchImpl(`/api/gnss-integrity?${params}`, {
+        signal,
+      });
+      if (!response.ok) {
+        const limited = response.status === 429;
+        const retryAfterMs = retryDelay(
+          response.headers.get('retry-after'),
+          now(),
+        );
+        throw Object.assign(
+          new Error(
+            limited
+              ? 'GNSS feed rate limited (HTTP 429)'
+              : `GNSS feed unavailable (HTTP ${response.status})`,
+          ),
+          {
+            status: response.status,
+            retryable: limited || response.status >= 500,
+            retryAfterMs: retryAfterMs ?? (limited ? 60000 : null),
+          },
+        );
+      }
+      const payload = await readResponseJsonCapped(
+        response,
+        4 * 1024 * 1024,
+        signal,
+      );
+      signal?.throwIfAborted();
+      if (!Array.isArray(payload?.rows))
+        throw new Error('Malformed GNSS integrity snapshot');
+      // The snapshot's age (measured on the proxy's clock) dates every row in
+      // the rolling window; an undated snapshot could only be treated as new,
+      // so it is refused.
+      if (!Number.isFinite(payload.ageMs) || payload.ageMs < 0)
+        throw new Error('GNSS integrity snapshot has no observation time');
+      return {
+        rows: payload.rows,
+        ageMs: payload.ageMs,
+        fetchedAt: Number.isFinite(payload.fetchedAt)
+          ? payload.fetchedAt
+          : null,
+        stale: payload.stale === true,
+        classifier:
+          typeof payload.classifier === 'string' ? payload.classifier : null,
+      };
+    },
+  };
+}

src/layers/gnss/source.test.mjs

@@ -0,0 +1,111 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import { createAdsbGnssSource } from './source.js';
+
+test('the source asks the same-origin proxy for the view anchor', async () => {
+  const calls = [];
+  const source = createAdsbGnssSource({
+    fetchImpl: async (url, options) => {
+      calls.push(url);
+      assert.ok(options.signal instanceof AbortSignal);
+      return Response.json({
+        fetchedAt: 5,
+        ageMs: 0,
+        classifier: 'gev-nic-nacp-v2',
+        rows: [{ hex: 'abc123' }],
+      });
+    },
+  });
+  const snapshot = await source.getSnapshot(
+    { latitude: 50.06143, longitude: 19.93658 },
+    { signal: new AbortController().signal },
+  );
+  assert.deepEqual(calls, ['/api/gnss-integrity?lat=50&lon=20']);
+  assert.deepEqual(snapshot, {
+    rows: [{ hex: 'abc123' }],
+    ageMs: 0,
+    fetchedAt: 5,
+    stale: false,
+    classifier: 'gev-nic-nacp-v2',
+  });
+});
+
+test('the source reports stale proxy data and rejects bad input or responses', async () => {
+  const reply = (body, init) => async () => Response.json(body, init);
+  const stale = await createAdsbGnssSource({
+    fetchImpl: reply({ rows: [], fetchedAt: 7, ageMs: 90_000, stale: true }),
+  }).getSnapshot({ latitude: 1, longitude: 2 });
+  assert.equal(stale.stale, true);
+  assert.equal(stale.ageMs, 90_000, 'a stale reply keeps its observation age');
+  assert.equal(stale.fetchedAt, 7);
+  assert.equal(stale.classifier, null);
+  // Without an observation age the rows could only be dated as new.
+  for (const ageMs of [undefined, null, '7', -1, Number.NaN])
+    await assert.rejects(
+      createAdsbGnssSource({
+        fetchImpl: reply({ rows: [], fetchedAt: 7, ageMs }),
+      }).getSnapshot({ latitude: 1, longitude: 2 }),
+      /no observation time/,
+    );
+
+  await assert.rejects(
+    createAdsbGnssSource({ fetchImpl: reply({}) }).getSnapshot({}),
+    /view anchor/,
+  );
+  await assert.rejects(
+    createAdsbGnssSource({
+      fetchImpl: reply({ error: 'x' }, { status: 502 }),
+    }).getSnapshot({ latitude: 1, longitude: 2 }),
+    /HTTP 502/,
+  );
+  await assert.rejects(
+    createAdsbGnssSource({ fetchImpl: reply({ rows: 'no' }) }).getSnapshot({
+      latitude: 1,
+      longitude: 2,
+    }),
+    /Malformed/,
+  );
+  const controller = new AbortController();
+  controller.abort();
+  await assert.rejects(
+    createAdsbGnssSource({ fetchImpl: reply({ rows: [] }) }).getSnapshot(
+      { latitude: 1, longitude: 2 },
+      { signal: controller.signal },
+    ),
+  );
+});
+
+test('HTTP failures distinguish rate limiting, preserve Retry-After and classify retryability', async () => {
+  const at = Date.UTC(2026, 9, 13, 12);
+  for (const [status, header, delay, retryable] of [
+    [429, '3600', 3600000, true],
+    [429, new Date(at + 3600000).toUTCString(), 3600000, true],
+    [429, null, 60000, true],
+    [429, 'Infinity', 60000, true],
+    [502, '5', 5000, true],
+    [502, null, null, true],
+    [400, null, null, false],
+  ]) {
+    const source = createAdsbGnssSource({
+      now: () => at,
+      fetchImpl: async () =>
+        Response.json(
+          {},
+          { status, headers: header ? { 'Retry-After': header } : {} },
+        ),
+    });
+    await assert.rejects(
+      source.getSnapshot({ latitude: 50, longitude: 20 }),
+      (e) => {
+        assert.equal(e.status, status);
+        assert.equal(e.retryAfterMs, delay);
+        assert.equal(e.retryable, retryable);
+        assert.match(
+          e.message,
+          status === 429 ? /rate limited/ : /feed unavailable/,
+        );
+        return true;
+      },
+    );
+  }
+});

src/layers/military/policy.js

@@ -6,6 +6,7 @@ export {
   ERROR_BACKOFF_INTERVAL,
 } from './recordPolicy.js';
 import * as Cesium from 'cesium';
+import { EMERGENCY_TINT_CSS } from '../../data/aircraftEmergency.js';
 
 /**
  * @module militaryFlights
@@ -40,6 +41,11 @@ export const MIL_ICON_COLOR = Cesium.Color.fromCssColorString('#FFB800');
 
 export const TRACKED_ICON_COLOR = Cesium.Color.fromCssColorString('#FFD166');
 
+/** @constant {Cesium.Color} Red tint for aircraft broadcasting an emergency (mirror of flights) */
+
+export const EMERGENCY_ICON_COLOR =
+  Cesium.Color.fromCssColorString(EMERGENCY_TINT_CSS);
+
 // --- Ground traffic (owner reversal 2026-07-03; mirror of flights.js) ---------------
 // adsb.lol/readsb flags ground traffic with alt_baro === "ground" (no separate
 // boolean). Such aircraft are RENDERED instead of floating at the 3 km altitude

src/layers/military/queries.js

@@ -9,6 +9,7 @@ import {
   CONTACT_MATCH_TIER,
 } from '../../data/contactMatch.js';
 import { LANDED_ALT_MAX_FT, LANDED_SPEED_MAX_MPS } from './policy.js';
+import { emergencyBroadcastPhrase } from '../../data/aircraftEmergency.js';
 
 export function createQueries({
   flightState,
@@ -133,6 +134,10 @@ export function createQueries({
         flightState.records.missingPolls.get(icao24) ||
         flightState.feed._backoff,
       ),
+      // This poll's transponder broadcast (not sticky; see records.js).
+      squawk: info?.squawk ?? null,
+      emergency: info?.emergency ? { ...info.emergency } : null,
+      emergencyBroadcast: emergencyBroadcastPhrase(info?.emergency),
     };
   }
 
@@ -156,7 +161,9 @@ export function createQueries({
    *   lon: number|null, altitudeM: number|null, speedMps: number|null,
    *   heading: number|null, verticalRateMps: number|null, onGround: boolean,
    *   military: boolean, aircraftClass: string|null, originCountry: null,
-   *   operator: string|null, routeOrigin: null, routeDestination: null}}
+   *   operator: string|null, squawk: string|null, emergency: boolean,
+   *   emergencyKind: string|null, emergencySource: 'squawk'|'ads-b'|null,
+   *   emergencyBroadcast: string|null, lastContactAtMs: number|null, routeOrigin: null, routeDestination: null}}
    */
 
   function mapAnalystRecord(icao24, info) {
@@ -187,6 +194,20 @@ export function createQueries({
       aircraftClass: tr3bAircraftClass(icao24, text(info?.klass)),
       originCountry: null,
       operator: text(info?.operator),
+      squawk: text(info?.squawk),
+      // True while this poll broadcast an emergency (7500/7600/7700 or the
+      // ADS-B status); priority statuses (lifeguard, minfuel) report the kind
+      // without the flag.
+      emergency: info?.emergency?.severity === 'emergency',
+      emergencyKind: text(info?.emergency?.kind),
+      // Provenance, so a summary can say "broadcasting squawk 7700" rather
+      // than "ADS-B reports general emergency" (or flatten both): 'squawk'
+      // when the Mode A code names the status, 'ads-b' for the readsb field.
+      emergencySource: text(info?.emergency?.source),
+      emergencyBroadcast: emergencyBroadcastPhrase(info?.emergency),
+      // Latest known general aircraft-message contact, retained if a poll
+      // has no time. This is not the receipt time of the current status.
+      lastContactAtMs: num(info?.lastContactEpochMs),
       routeOrigin: null,
       routeDestination: null,
     };

src/layers/military/records.js

@@ -1,6 +1,7 @@
 import { pickRenderAltitudeM } from '../../data/renderAltitude.js';
 import { stickyText, stickyNumber } from '../../data/aircraftMeta.js';
 import { classifyAircraft } from '../../data/aircraftClass.js';
+import { aircraftEmergency } from '../../data/aircraftEmergency.js';
 import {
   GROUND_FLOOR_WARM_MAX_ALT_M,
   LANDED_MISSING_POLL_LIMIT,
@@ -161,6 +162,9 @@ export class MilitaryFlightRecords {
         null,
       ),
       turnRateDps: prevMeta?.turnRateDps || 0,
+      // Per poll, NOT sticky (mirror of flights): a cleared code clears here.
+      squawk: aircraft.squawk ?? null,
+      emergency: aircraftEmergency(aircraft),
       onGround,
       // Round 7: sticky airborne history (see _likelyLanded).
       wasAirborne: prevMeta?.wasAirborne === true || !onGround,

src/layers/military/records.test.mjs

@@ -98,3 +98,19 @@ test('military records keep bounded partial retention and release metadata only
     'remove',
   );
 });
+
+test('military emergency status follows the latest poll instead of sticking', () => {
+  const records = store();
+  const first = records.receive(
+    observation({ squawk: '1234', emergency: 'minfuel' }),
+    context(),
+  );
+  assert.equal(first.meta.squawk, '1234');
+  assert.equal(first.meta.emergency.kind, 'minfuel');
+  assert.equal(first.meta.emergency.severity, 'priority');
+  const next = records.receive(
+    observation({ squawk: '1234', emergency: 'none' }),
+    context(),
+  );
+  assert.equal(next.meta.emergency, null);
+});

src/layers/military/rendering.js

@@ -18,6 +18,7 @@ import {
   screenProjectedRotation,
 } from '../../data/iconOrientation.js';
 import { limitCourseStep, courseSlewCapDps } from '../../data/motionModel.js';
+import { isEmergency } from '../../data/aircraftEmergency.js';
 import {
   PLANE_MODEL_SCALE,
   PLANE_MODEL_URL,
@@ -33,6 +34,7 @@ import {
   COCKPIT_CONTACT_SIZE_PX,
   MIL_ICON_COLOR,
   TRACKED_ICON_COLOR,
+  EMERGENCY_ICON_COLOR,
   MODEL_ALT_CEIL_M,
   MODEL_MAX_ALL,
   MODEL_MAX,
@@ -159,7 +161,7 @@ export function createRendering({
       bb.height = COCKPIT_CONTACT_SIZE_PX;
       bb.scale = limbScale;
       bb.scaleByDistance = _cockpitBillboardScaleByDistance();
-      bb.color = MIL_ICON_COLOR.withAlpha(freshnessAlpha);
+      bb.color = _fleetBillboardColor(icao24).withAlpha(freshnessAlpha);
       bb.rotation = 0;
       return;
     }
@@ -173,7 +175,9 @@ export function createRendering({
     bb.height = icao24 === flightState._trackedIcao ? 24 : 20;
     bb.scale = _militaryBillboardScale(icao24) * limbScale;
     bb.scaleByDistance = _normalBillboardScaleByDistance();
-    bb.color = MIL_ICON_COLOR.withAlpha(cyberSonarBaseAlpha(bb));
+    bb.color = _fleetBillboardColor(icao24, meta).withAlpha(
+      cyberSonarBaseAlpha(bb),
+    );
   }
 
   /** Sprite kind for one contact's billboard. Identity for every aircraft except
@@ -189,7 +193,17 @@ export function createRendering({
 
   function _modelColor(icao24) {
     if (icao24 === flightState._trackedIcao) return TRACKED_ICON_COLOR;
-    return MIL_ICON_COLOR;
+    return _fleetBillboardColor(icao24);
+  }
+
+  /** Fleet (untracked) tint: red while the latest poll broadcast an emergency,
+   *  amber otherwise. Cockpit far-contact dots use it too. */
+
+  function _fleetBillboardColor(
+    icao24,
+    info = flightState.records.data.get(icao24),
+  ) {
+    return isEmergency(info?.emergency) ? EMERGENCY_ICON_COLOR : MIL_ICON_COLOR;
   }
 
   /** The FLEET's 3D-model regime: models3d enabled AND the camera zoomed in past the altitude
@@ -965,7 +979,7 @@ export function createRendering({
       const isCockpitNear =
         flightState._cockpitContactMode &&
         flightState._cockpitNearContacts.has(icao24);
-      const baseColor = MIL_ICON_COLOR;
+      const baseColor = _fleetBillboardColor(icao24, info);
       const treatment = applyAircraftBillboardTreatment({
         billboard: bb,
         baseScale:
@@ -1082,6 +1096,7 @@ export function createRendering({
     _applyFleetBillboardPresentation,
     _iconKind,
     _modelColor,
+    _fleetBillboardColor,
     _modelRegimeActive,
     _modelCap,
     _modelAddDistM,

src/layers/military/snapshotRenderer.js

@@ -1,4 +1,5 @@
 import * as Cesium from 'cesium';
+import { cyberSonarBaseAlpha } from '../../cyberSonar.js';
 import { CLASS_SCALE_2D } from '../../data/aircraftClass.js';
 import {
   turnRateFromFixHistory,
@@ -7,12 +8,7 @@ import {
 } from '../../data/motionModel.js';
 import { aircraftIcon } from '../../data/aircraftIcons.js';
 import { POSITION_HISTORY_LIMIT } from './recordPolicy.js';
-import {
-  BILLBOARD_SCALE,
-  GROUND_SCALE,
-  TRACKED_ICON_COLOR,
-  MIL_ICON_COLOR,
-} from './policy.js';
+import { BILLBOARD_SCALE, GROUND_SCALE, TRACKED_ICON_COLOR } from './policy.js';
 
 /** Apply military record changes to Cesium resources and existing follow operations. */
 export function createMilitarySnapshotRenderer({
@@ -125,6 +121,11 @@ export function createMilitarySnapshotRenderer({
 
       if (flightState._billboards.has(icao24)) {
         const bb = flightState._billboards.get(icao24);
+        if (!isTracked) {
+          bb.color = rendering
+            ._fleetBillboardColor(icao24, meta)
+            .withAlpha(cyberSonarBaseAlpha(bb));
+        }
         // Position AND rotation are owned by the fleet pass (_fleetTick);
         // course changes land on the next rotation pass (forced below).
         // Ground flips (landing/takeoff) restyle this SAME billboard in
@@ -161,7 +162,9 @@ export function createMilitarySnapshotRenderer({
           // Screen-projected rotation lands on the next fleet tick.
           rotation: 0,
           alignedAxis: Cesium.Cartesian3.ZERO,
-          color: isTracked ? TRACKED_ICON_COLOR : MIL_ICON_COLOR,
+          color: isTracked
+            ? TRACKED_ICON_COLOR
+            : rendering._fleetBillboardColor(icao24, meta),
           sizeInMeters: false,
           scaleByDistance: rendering._normalBillboardScaleByDistance(),
           // Grounded/near-surface planes sit at/below the photoreal tile

src/layers/military/tracking.js

@@ -21,7 +21,6 @@ import {
   TRAIL_COLOR,
   BILLBOARD_SCALE,
   GROUND_SCALE,
-  MIL_ICON_COLOR,
   AMBER_TRANSPARENT,
   TRACKED_ICON_COLOR,
 } from './policy.js';
@@ -780,12 +779,16 @@ export function createTracking({
       bb.width = 20;
       bb.height = 20;
       // Ground-aware restore (a plane untracked while taxiing comes back at
-      // ground scale; tint is full amber on the ground and in the air).
+      // ground scale; the fleet tint is amber, or red while broadcasting an
+      // emergency, on the ground and in the air).
       bb.scale =
         BILLBOARD_SCALE *
         (CLASS_SCALE_2D[meta?.klass] || 1) *
         (meta?.onGround ? GROUND_SCALE : 1);
-      bb.color = MIL_ICON_COLOR;
+      bb.color = parts.rendering._fleetBillboardColor(
+        flightState._trackedIcao,
+        meta,
+      );
       bb.rotation = flightState._lastTrackedRotation;
     }
     flightState._lastCamPoseSig = ''; // force a fleet rotation pass on the next tick

src/layers/recentImagery/imagery-box-missing-edge.test.mjs

@@ -0,0 +1,48 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  boxCentre,
+  boxFromRectangle,
+  dequantizeBox,
+  validateBox,
+} from './model.js';
+import { searchHls } from './catalog.js';
+
+test('missing imagery edges do not turn into invented zero coordinates', () => {
+  for (const value of [null, undefined, '', ' ', false, true]) {
+    const box = { west: value, south: 0, east: 1, north: 1 };
+    assert.equal(validateBox(box).ok, false);
+    assert.equal(validateBox(box).reason, 'invalid');
+    assert.equal(boxCentre(box), null);
+  }
+  assert.equal(validateBox({ west: 0, south: 0, east: 1, north: 1 }).ok, true);
+  assert.equal(
+    validateBox({ west: '0', south: '0', east: '1', north: '1' }).ok,
+    true,
+  );
+});
+
+test('every edge and every box entry point refuses a missing edge', async () => {
+  const blanks = [null, undefined, '', ' ', false, [], {}];
+  for (const edge of ['west', 'south', 'east', 'north']) {
+    for (const value of blanks) {
+      const box = { west: 1, south: 1, east: 2, north: 2, [edge]: value };
+      assert.equal(validateBox(box).ok, false, `${edge}=${String(value)}`);
+      // Share-link integers and Cesium radians are converted per edge.
+      assert.equal(dequantizeBox(box), null, `share ${edge}`);
+      assert.equal(boxFromRectangle(box), null, `radians ${edge}`);
+    }
+  }
+  let fetched = false;
+  await assert.rejects(
+    searchHls({
+      box: { west: ' ', south: 1, east: 2, north: 2 },
+      fetchImpl: async () => {
+        fetched = true;
+      },
+    }),
+    TypeError,
+  );
+  assert.equal(fetched, false);
+  assert.ok(dequantizeBox({ west: 0, south: 0, east: 100000, north: 100000 }));
+});

src/layers/recentImagery/model.js

@@ -75,6 +75,14 @@ const pad2 = (value) => String(value).padStart(2, '0');
  * east are not swapped: west > east crosses the dateline and `validateBox`
  * rejects it. Null when any edge is nonfinite.
  */
+/** A box edge as a number, or null when it is missing, blank or not numeric. */
+function edgeNumber(value) {
+  if (typeof value === 'number') return Number.isFinite(value) ? value : null;
+  if (typeof value !== 'string' || !value.trim()) return null;
+  const number = Number(value);
+  return Number.isFinite(number) ? number : null;
+}
+
 function normalizeBox(box) {
   if (!box || typeof box !== 'object') return null;
   const [west, south, east, north] = [
@@ -82,8 +90,8 @@ function normalizeBox(box) {
     box.south,
     box.east,
     box.north,
-  ].map(Number);
-  if (![west, south, east, north].every(Number.isFinite)) return null;
+  ].map(edgeNumber);
+  if ([west, south, east, north].some((edge) => edge == null)) return null;
   return {
     west,
     south: Math.min(south, north),
@@ -211,11 +219,16 @@ export function boxFromPin(lon, lat, sideKm = PIN_BOX_SIDE_KM) {
 
 function mapBox(box, fn) {
   if (!box || typeof box !== 'object') return null;
+  // Converting first would turn a blank edge into 0 before normalizeBox sees it.
+  const edge = (value) => {
+    const number = edgeNumber(value);
+    return number == null ? null : fn(number);
+  };
   return normalizeBox({
-    west: fn(box.west),
-    south: fn(box.south),
-    east: fn(box.east),
-    north: fn(box.north),
+    west: edge(box.west),
+    south: edge(box.south),
+    east: edge(box.east),
+    north: edge(box.north),
   });
 }
 

src/layers/streetLevel/street-level-unique-tiles.test.mjs

@@ -0,0 +1,31 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { tilesForBbox } from './tileMath.js';
+
+test('reachable polar dateline coverage ranks 24 distinct tiles before overview truncation', () => {
+  // coverage uses the actual view bbox above zoom 1; polar views can wrap.
+  const bbox = [-10, 60, -20, 85];
+  const result = tilesForBbox(bbox, 3);
+  const keys = result.tiles.map((tile) => `${tile.x}/${tile.y}/${tile.z}`);
+  assert.equal(keys.length, 24);
+  assert.equal(new Set(keys).size, 24);
+  assert.equal(result.total, 24);
+  assert.equal(result.truncated, false);
+  const overview = tilesForBbox(bbox, 3, { limit: 16 });
+  assert.equal(overview.total, 24);
+  assert.equal(overview.tiles.length, 16);
+  assert.equal(
+    new Set(overview.tiles.map((tile) => `${tile.x}/${tile.y}/${tile.z}`)).size,
+    16,
+  );
+  assert.equal(overview.truncated, true);
+});
+
+test('a limit that fits every distinct tile is not spent on repeats', () => {
+  // Before de-duplication this box yielded 27 entries for 24 tiles, so a
+  // 24-slot overview held repeats and still reported itself truncated.
+  const result = tilesForBbox([-10, 60, -20, 85], 3, { limit: 24 });
+  const keys = result.tiles.map((tile) => `${tile.x}/${tile.y}/${tile.z}`);
+  assert.equal(new Set(keys).size, 24);
+  assert.equal(result.truncated, false);
+});

src/layers/streetLevel/tileMath.js

@@ -146,8 +146,16 @@ export function tilesForBbox(bbox, z, { limit = Infinity, focus = null } = {}) {
         const dx = Math.abs(tile.x - centre.x);
         return Math.min(dx, n - dx) ** 2 + (tile.y - centre.y) ** 2;
       };
-  // Each tile's distance is computed once; ties keep their row order.
-  const ranked = tiles
+  // The date-line halves share a column when the gap between east and west is
+  // narrower than a tile; count that column once so a capped overview does not
+  // spend its slots on repeats. Each tile's distance is computed once; ties keep
+  // their row order.
+  const unique = [
+    ...new Map(
+      tiles.map((tile) => [`${tile.x}/${tile.y}/${tile.z}`, tile]),
+    ).values(),
+  ];
+  const ranked = unique
     .map((tile) => ({ tile, d: distance2(tile) }))
     .sort((a, b) => a.d - b.d)
     .map(({ tile }) => tile);

src/maps/controller.js

@@ -131,7 +131,8 @@ export class MapSourceController {
    * @returns {() => void} Unsubscribe.
    */
   subscribe(listener) {
-    if (typeof listener !== 'function') return () => {};
+    // A destroyed controller never settles again, so it takes no listeners.
+    if (typeof listener !== 'function' || this._destroyed) return () => {};
     this._subscribers.add(listener);
     return () => {
       this._subscribers.delete(listener);
@@ -142,6 +143,8 @@ export class MapSourceController {
     if (this._destroyed || !this._subscribers.size) return;
     const state = this.getState();
     for (const listener of [...this._subscribers]) {
+      if (this._destroyed) return;
+      if (!this._subscribers.has(listener)) continue;
       try {
         listener(state);
       } catch (error) {

src/maps/map-subscription-ownership.test.mjs

@@ -0,0 +1,89 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { MapSourceController } from './controller.js';
+function fixture() {
+  return new MapSourceController(
+    {
+      scene: {
+        globe: { show: true },
+        requestRender() {},
+        frameState: {
+          creditDisplay: { addStaticCredit() {}, removeStaticCredit() {} },
+        },
+        primitives: { add() {}, remove() {} },
+      },
+      imageryLayers: { add() {}, remove() {} },
+    },
+    {
+      registry: {
+        defaultId: 'fixture',
+        sources: [
+          {
+            descriptor: { id: 'fixture', label: 'Fixture', kind: 'imagery' },
+            imagery: async () => ({}),
+          },
+        ],
+      },
+      createImageryLayer: (provider) => ({ provider }),
+    },
+  );
+}
+test('an unsubscribed owner is skipped in the same map settlement delivery', async () => {
+  const controller = fixture();
+  const calls = [];
+  let detach;
+  controller.subscribe(() => {
+    calls.push('first');
+    detach();
+  });
+  detach = controller.subscribe(() => calls.push('detached'));
+  controller.subscribe(() => calls.push('last'));
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['first', 'last']);
+  controller.destroy();
+});
+test('destroying the controller during delivery stops remaining listeners', async () => {
+  const controller = fixture();
+  const calls = [];
+  controller.subscribe(() => {
+    calls.push('destroy');
+    controller.destroy();
+  });
+  controller.subscribe(() => calls.push('detached'));
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['destroy']);
+});
+
+test('a listener re-added after destroy during delivery is not called', async () => {
+  const controller = fixture();
+  const calls = [];
+  const later = () => calls.push('later');
+  controller.subscribe(() => {
+    calls.push('destroy');
+    controller.destroy();
+    controller.subscribe(later);
+  });
+  controller.subscribe(later);
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['destroy']);
+});
+
+test('delivery order: added during delivery waits, duplicates run once, re-added runs', async () => {
+  const controller = fixture();
+  const calls = [];
+  const twice = () => calls.push('twice');
+  const readded = () => calls.push('readded');
+  let offReadded;
+  controller.subscribe(() => {
+    calls.push('first');
+    controller.subscribe(() => calls.push('added-late'));
+    offReadded();
+    controller.subscribe(readded);
+  });
+  controller.subscribe(twice);
+  controller.subscribe(twice);
+  offReadded = controller.subscribe(readded);
+  await controller.setStack('fixture');
+  assert.deepEqual(calls, ['first', 'twice', 'readded']);
+  controller.destroy();
+});

src/services/terrainHeights.js

@@ -272,28 +272,26 @@ export function createTerrainHeights({
     const uncached = [];
     const seenKeys = new Set();
     const now = Date.now();
+    // What this call resolved or found warm, so the assembly below can report a
+    // point even if a later chunk's writes pushed it past CACHE_MAX_ENTRIES.
+    // Without it a batch big enough to evict its own entries would report
+    // points as unresolved that it had in fact resolved.
+    const resolvedThisCall = new Map();
     for (const item of work) {
-      const entry = cache.get(item.key);
+      const entry = cacheTouch(item.key);
       const fallbackCooling =
         entry?.source === 'geoid-fallback' &&
         Number.isFinite(entry.retryAt) &&
         now < entry.retryAt;
-      if (
-        (entry && entry.source === 'reearth') ||
-        fallbackCooling ||
-        seenKeys.has(item.key)
-      )
+      if ((entry && entry.source === 'reearth') || fallbackCooling) {
+        resolvedThisCall.set(item.key, entry);
         continue;
+      }
+      if (seenKeys.has(item.key)) continue;
       seenKeys.add(item.key);
       uncached.push(item);
     }
 
-    // What this call resolved, so the assembly below can report a point even
-    // if a later chunk's writes pushed it past CACHE_MAX_ENTRIES. Without it a
-    // batch big enough to evict its own earlier chunks would report points as
-    // unresolved that it had in fact just resolved.
-    const resolvedThisCall = new Map();
-
     // Resolve the network path in sequential <=CHUNK_SIZE chunks. Each chunk's
     // failure is isolated to that chunk's points (geoid fallback), so a single
     // bad chunk doesn't lose results for the rest of a large batch.

src/services/terrainHeights.test.mjs

@@ -114,6 +114,47 @@ test('a batch larger than the cache bound still reports every point it resolved'
   assert.equal(warm.length, 4);
 });
 
+test('warm batch consumers retain their terrain cells ahead of unused cells', async () => {
+  let calls = 0;
+  const terrain = createTerrainHeights({
+    maxCacheEntries: 2,
+    source: {
+      async getHeights(points) {
+        calls++;
+        return points.map((p) => ({ ellipsoid: 100 + p.lon }));
+      },
+    },
+  });
+  const p = (lon) => ({ lat: 0, lon });
+  await terrain.resolveEllipsoidalGround([p(1)]);
+  await terrain.resolveEllipsoidalGround([p(2)]);
+  await terrain.resolveEllipsoidalGround([p(1)]);
+  assert.equal(calls, 2);
+  await terrain.resolveEllipsoidalGround([p(3)]);
+  assert.equal(terrain.cachedEllipsoidalGround(0, 1), 101);
+  assert.equal(terrain.cachedEllipsoidalGround(0, 2), null);
+  assert.equal(calls, 3);
+});
+
+test('a batch still reports its warm points after its own fetches evict them', async () => {
+  const terrain = createTerrainHeights({
+    source: stubSource(),
+    maxCacheEntries: 2,
+  });
+  await terrain.resolveEllipsoidalGround([pointAt(0)]);
+
+  const results = await terrain.resolveEllipsoidalGround([
+    pointAt(0),
+    pointAt(1),
+    pointAt(2),
+  ]);
+
+  results.forEach((result, i) => {
+    assert.equal(result.source, 'reearth', `point ${i} reported resolved`);
+    assert.equal(result.ellipsoid, heightAt(lonAt(i)));
+  });
+});
+
 test('an out-of-range cache bound falls back to the default instead of disabling the cache', async () => {
   for (const maxCacheEntries of [0, -1, Number.NaN, undefined]) {
     const terrain = createTerrainHeights({

src/sources/live/aircraft.js

@@ -1,3 +1,4 @@
+import { normalizeSquawk } from '../../data/aircraftEmergency.js';
 import {
   admitRecords,
   cleanText,
@@ -30,6 +31,9 @@ export function normalizeOpenSkyAircraft(row) {
     typeCode: null,
     registration: null,
     operator: null,
+    squawk: normalizeSquawk(row[14]),
+    // State vectors carry no ADS-B emergency field; the squawk stands alone.
+    emergency: undefined,
   };
 }
 
@@ -68,6 +72,8 @@ export function normalizeReadsbAircraft(row, snapshotTimeMs) {
     typeCode: cleanText(row.t),
     registration: cleanText(row.r),
     operator: cleanText(row.ownOp),
+    squawk: normalizeSquawk(row.squawk),
+    emergency: cleanText(row.emergency).toLowerCase() || null,
   };
 }
 
@@ -82,7 +88,13 @@ export function openSkySnapshot(
 ) {
   const admitted = admitRecords(
     payload?.states,
-    normalizeOpenSkyAircraft,
+    (row) => {
+      const record = normalizeOpenSkyAircraft(row);
+      const statuses = payload?.emergencyByIcao;
+      if (record && statuses && Object.hasOwn(statuses, record.id))
+        record.emergency = cleanText(statuses[record.id]).toLowerCase() || null;
+      return record;
+    },
     'OpenSky',
   );
   const observedAtMs = epoch(payload?.time, 1000);

src/sources/live/contract.test.mjs

@@ -313,3 +313,23 @@ test('identity lookup validates its response and honors body-parse cancellation'
     name: 'AbortError',
   });
 });
+
+test('squawks are validated and omitted OpenSky status differs from an explicit ADS-B clear', () => {
+  const squawking = [...aircraft, '7700'];
+  const civil = openSkySnapshot({ states: [squawking] }, { now }).records[0];
+  assert.equal(civil.squawk, '7700');
+  assert.equal(civil.emergency, undefined);
+  assert.equal(openSkySnapshot({ states: [aircraft] }).records[0].squawk, null);
+  const mil = normalizeReadsbAircraft(
+    { hex: 'abc123', lat: 30, lon: -97, squawk: '7600', emergency: 'NORDO' },
+    now,
+  );
+  assert.equal(mil.squawk, '7600');
+  assert.equal(mil.emergency, 'nordo');
+  const quiet = normalizeReadsbAircraft(
+    { hex: 'abc123', lat: 30, lon: -97 },
+    now,
+  );
+  assert.equal(quiet.squawk, null);
+  assert.equal(quiet.emergency, null);
+});

src/sources/reference.js

@@ -1,6 +1,7 @@
 import { createUsgsEarthquakeSource } from '../layers/earthquakes/source.js';
 import { createWfigsPerimeterSource } from '../layers/perimeters/source.js';
 import { createBundledCableSource } from '../layers/submarineCables/bundledSource.js';
+import { createAdsbGnssSource } from '../layers/gnss/source.js';
 
 /** Construct the existing reference feeds independently of application setup. */
 export function createReferenceSources() {
@@ -8,5 +9,6 @@ export function createReferenceSources() {
     earthquakes: createUsgsEarthquakeSource(),
     'fire-perimeters': createWfigsPerimeterSource(),
     cables: createBundledCableSource(),
+    'gnss-integrity': createAdsbGnssSource(),
   };
 }

src/sources/reference.test.mjs

@@ -16,12 +16,15 @@ test('reference factories retain compatibility without starting acquisition or s
     'earthquakes',
     'fire-perimeters',
     'cables',
+    'gnss-integrity',
   ]);
   assert.notEqual(first.earthquakes, second.earthquakes);
   assert.notEqual(first['fire-perimeters'], second['fire-perimeters']);
   assert.notEqual(first.cables, second.cables);
+  assert.notEqual(first['gnss-integrity'], second['gnss-integrity']);
   assert.equal(typeof first.earthquakes.getSnapshot, 'function');
   assert.equal(typeof first['fire-perimeters'].getSnapshot, 'function');
   assert.equal(typeof first.cables.fetch, 'function');
+  assert.equal(typeof first['gnss-integrity'].getSnapshot, 'function');
   assert.equal(requests, 0);
 });

src/tooling/previewServing.test.mjs

@@ -10,6 +10,7 @@ import { makeFixtureRoot } from './fixtureRoot.mjs';
 test('data providers have both hooks; credential editing stays development-only', () => {
   const plugins = localProviderPlugins();
   assert.ok(plugins.some(({ name }) => name === 'fire-perimeters'));
+  assert.ok(plugins.some(({ name }) => name === 'gnss-integrity'));
   for (const plugin of plugins) {
     if (plugin.name === 'gev-key-setup') {
       assert.equal(plugin.configurePreviewServer, undefined);
@@ -103,6 +104,7 @@ test('real dev and built-preview servers serve provider JSON and terminate unkno
         ['/api/adsbdb/type/invalid', 400],
         ['/api/firms/status', 200],
         ['/api/fire-perimeters/inciweb/publication/invalid', 400],
+        ['/api/gnss-integrity?lat=invalid', 400],
         ['/api/terrain/heights?points=invalid', 400],
         ['/api/overpass', 405],
         ['/api/overpass/status', 200],

src/tools/results.js

@@ -24,7 +24,9 @@ export function capRows(rows, limit = DEFAULT_LIMIT) {
 
 /** Format an epoch millisecond time as ISO 8601, or null. */
 export function isoTime(ms) {
-  return Number.isFinite(ms) ? new Date(ms).toISOString() : null;
+  if (!Number.isFinite(ms)) return null;
+  const date = new Date(ms);
+  return Number.isFinite(date.getTime()) ? date.toISOString() : null;
 }
 
 /** "1 earthquake", "3 earthquakes". */

src/tools/tool-timestamp-range.test.mjs

@@ -0,0 +1,59 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { isoTime } from './results.js';
+import { getBikeShare } from './queries/mobility.js';
+test('out-of-range finite timestamps are unknown rather than throwing', async () => {
+  for (const value of [1e30, -1e30, NaN, Infinity, null])
+    assert.equal(isoTime(value), null);
+  assert.equal(isoTime(0), '1970-01-01T00:00:00.000Z');
+  assert.equal(isoTime(8640000000000000), '+275760-09-13T00:00:00.000Z');
+  assert.equal(isoTime(-8640000000000000), '-271821-04-20T00:00:00.000Z');
+  for (const value of [8640000000000001, -8640000000000001, -Infinity])
+    assert.equal(isoTime(value), null);
+  assert.equal(isoTime(-1), '1969-12-31T23:59:59.999Z');
+  const station = {
+    station_id: 's1',
+    name: 'Fixture',
+    lat: 0,
+    lon: 0,
+    capacity: 4,
+  };
+  const result = await getBikeShare.run(
+    { area: { bbox: [-1, -1, 1, 1] } },
+    {
+      services: {
+        bikeshare: {
+          systems: [
+            {
+              id: 'fixture',
+              city: 'Fixture',
+              centerLat: 0,
+              centerLon: 0,
+              loadRadiusKm: 30,
+              stationInformationUrl: 'information',
+              stationStatusUrl: 'status',
+            },
+          ],
+          async getStations(url) {
+            return {
+              data: {
+                stations:
+                  url === 'information'
+                    ? [station]
+                    : [
+                        {
+                          station_id: 's1',
+                          last_reported: 1e30,
+                          num_bikes_available: 2,
+                        },
+                      ],
+              },
+            };
+          },
+        },
+      },
+    },
+  );
+  assert.equal(result.data.returned, 1);
+  assert.equal(result.data.rows[0].last_reported, null);
+});

src/ui/cockpitInstruments.js

@@ -12,6 +12,7 @@ import {
   compassDivisions,
   formatAltitudeRulerTick,
   formatCompassDivision,
+  formatCockpitEmergency,
   formatSpeedRulerTick,
   normalizeHeading,
   relativeBearing,
@@ -133,7 +134,15 @@ export function updateHud(
         : info.stale
           ? 'STALE FEED'
           : 'LIVE TRACK';
-    this.aircraftMeta.textContent = `${info.layerId === 'military' ? 'MILITARY' : 'COMMERCIAL'} · ${feedState} · COURSE ALIGNED`;
+    const fleet = info.layerId === 'military' ? 'MILITARY' : 'COMMERCIAL';
+    const emergency = formatCockpitEmergency(info.emergency);
+    this.aircraftMeta.textContent = emergency
+      ? `${fleet} · ${emergency} · ${feedState}`
+      : `${fleet} · ${feedState} · COURSE ALIGNED`;
+    this.aircraftMeta.classList.toggle(
+      'emergency',
+      info.emergency?.severity === 'emergency',
+    );
   }
   this.updateRoute(info);
   if (

src/ui/layerPanel.js

@@ -49,7 +49,13 @@ const PANEL_GROUPS = [
   },
   {
     label: 'Events',
-    ids: ['rocket-launches', 'earthquakes', 'local-firms', 'fire-perimeters'],
+    ids: [
+      'rocket-launches',
+      'earthquakes',
+      'local-firms',
+      'fire-perimeters',
+      'gnss-integrity',
+    ],
   },
   {
     label: 'Weather',

src/ui/styles/cockpit.css

@@ -43,6 +43,8 @@
 
 #cockpit-hud {
   --cockpit-accent: #00dcff;
+  /* Matches EMERGENCY_TINT_CSS in src/data/aircraftEmergency.js. */
+  --cockpit-emergency: #ff4444;
   --cockpit-side-panel-width: min(340px, 28vw);
   /* HUD bottom offset + tallest scaled telemetry block + 20px clear border. */
   --cockpit-bottom-rail-safe: calc(clamp(84px, 11vh, 118px) + 100px);
@@ -496,6 +498,10 @@ body.cockpit-mode:has(#left-panel-stack > .panel-collapsible:not(.collapsed))
   font-size: 7px;
   letter-spacing: 0.16em;
 }
+.cockpit-aircraft-meta.emergency {
+  color: var(--cockpit-emergency);
+  font-weight: 600;
+}
 .cockpit-mode-chip {
   margin-top: 2px;
   padding: 7px 11px;

src/ui/styles/cyber.css

@@ -2270,6 +2270,12 @@
   color: rgba(205, 225, 226, 0.48);
 }
 
+:root[data-ui-theme='cyber']
+  body.cockpit-mode
+  .cockpit-aircraft-meta.emergency {
+  color: var(--cyber-red-bright);
+}
+
 :root[data-ui-theme='cyber'] body.cockpit-mode .cockpit-vision-controls {
   margin-top: 0;
   border-color: rgba(105, 203, 209, 0.38);

src/voice/actionSchemas.test.mjs

@@ -36,8 +36,8 @@ test('the complete Realtime tool payload pins the manifest-generated layer relea
     // consolidated tool wording (each policy stated once); model-facing tools
     // omit top-level anyOf (OpenAI rejects it). Contacts list routing preserves
     // requested radius and center authority in descriptions only.
-    // Street Level adds its toggle enum values and generated alias hint.
-    '9eb113454c5af5e32e27ffcdc7919d0e4600ba1d204f8f175e071152be41ad0f',
+    // Street Level and GNSS extend the manifest; tracked and analyst aircraft describe broadcasts.
+    '9398815a573ab29ecc3ce527f6e1a2ad883804e7696e0444aebb11f973700d4b',
   );
 });
 

src/voice/gevActions.js

@@ -4809,7 +4809,12 @@ function compactAnalystItem(r) {
     if (!present(r[key]) || key in compact) continue;
     if (spec.type === 'time') {
       const ms = Number(r[key]);
-      if (Number.isFinite(ms)) compact.time = new Date(ms).toISOString();
+      // A finite value can still be past Date's range, where toISOString throws.
+      const time = new Date(ms);
+      if (Number.isFinite(time.getTime())) {
+        if (key === 'lastContactAtMs') compact.lastContactAtMs = ms;
+        else compact.time = time.toISOString();
+      }
     } else compact[key] = r[key];
   }
   if (present(r.ageHours)) compact.ageHours = r.ageHours;

src/voice/gevActions.test.mjs

@@ -3263,6 +3263,30 @@ test('ALPR common names toggle only the registered camera layer through the norm
   }
 });
 
+test('GNSS integrity and interference common names toggle only the GNSS layer through the normal voice action', async () => {
+  globalThis.window = globalThis.window || { clearTimeout, setTimeout, requestIdleCallback: null };
+  const viewer = { clock: { onTick: { addEventListener: () => () => {} } },
+    scene: { canvas: { addEventListener() {}, removeEventListener() {} } },
+    camera: { moveEnd: { addEventListener() {} } } };
+  const calls = [];
+  let enabled = false;
+  const dataManager = {
+    layers: new Map([['gnss-integrity', { module: {} }]]),
+    getAll: () => [{ id: 'gnss-integrity', name: 'GNSS Integrity' }],
+    isEnabled: () => enabled,
+    setEnabled: async (id, value) => { calls.push([id, value]); enabled = value; return true; },
+  };
+  const runner = createGevActionRunner({ viewer, styleManager: {}, dataManager });
+  for (const alias of ['gnss-integrity', 'gnss integrity', 'navigation integrity', 'low navigation accuracy', 'gnss interference', 'gps interference', 'gps jamming', 'gnss']) {
+    for (const value of [true, false]) {
+      const result = await runner('set_layer_visibility', { layerId: alias, enabled: value });
+      assert.equal(result.ok, true);
+      assert.equal(result.layerId, 'gnss-integrity');
+      assert.deepEqual(calls.at(-1), ['gnss-integrity', value]);
+    }
+  }
+});
+
 test('Local ADS-B common names toggle only the receiver layer through the normal voice action', async () => {
   globalThis.window = globalThis.window || { clearTimeout, setTimeout, requestIdleCallback: null };
   const viewer = { clock: { onTick: { addEventListener: () => () => {} } },
@@ -3459,6 +3483,26 @@ test('analyst_query refusals carry their code and the allowed values', async ()
   assert.match(ok.items[0].time, /^\d{4}-\d\d-\d\dT/);
 });
 
+test('analyst_query keeps its answer when one record has an out-of-range time', async () => {
+  globalThis.window = globalThis.window || { clearTimeout, setTimeout, requestIdleCallback: null };
+  const now = Date.now();
+  const earthquakes = {
+    getStats: () => ({ count: 2, lastUpdate: now }),
+    getAnalystRecords: () => [
+      { id: 'q', lat: 0, lon: 0, magnitude: 5, timeMs: now },
+      { id: 'r', lat: 1, lon: 1, magnitude: 4, timeMs: 8.64e15 + 1 },
+    ],
+  };
+  const { runner } = manifestRunner({ earthquakes }, { enabled: ['earthquakes'] });
+  const result = await runner('analyst_query', { layers: ['earthquakes'], scope: { kind: 'anywhere' } });
+  assert.equal(result.ok, true);
+  const q = result.items.find((item) => item.id === 'q');
+  assert.match(q.time, /^\d{4}-\d\d-\d\dT/);
+  const r = result.items.find((item) => item.id === 'r');
+  assert.ok(r, 'the record is still listed');
+  assert.equal(r.time, undefined, 'an unrepresentable time is omitted');
+});
+
 test('spoken layer names from the manifest reach the newer layers', async () => {
   globalThis.window = globalThis.window || { clearTimeout, setTimeout, requestIdleCallback: null };
   const stub = () => ({ getStats: () => ({ count: 0 }) });

src/voice/layerManifest.js

@@ -34,9 +34,29 @@ const AIRCRAFT_FIELDS = {
   aircraftClass: ['t'],
   military: ['f'],
   onGround: ['f'],
+  squawk: ['t'],
+  emergency: ['f'],
+  emergencyKind: ['t'],
+  emergencySource: ['t'],
+  emergencyBroadcast: ['t'],
+  lastContactAtMs: ['ms'],
 };
 
 const layers = [
+  {
+    id: 'gnss-integrity',
+    aliases: [
+      'gnss integrity',
+      'navigation integrity',
+      'low navigation accuracy',
+      'gnss interference',
+      'gps interference',
+      'gps jamming',
+      'gnss',
+    ],
+    context: false,
+    noQuery: 'navigation-integrity cells; no countable analyst records',
+  },
   {
     id: 'flights',
     track: true,