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@ -784,17 +784,163 @@ app.get('/api/satellites/tle', async (req, res) => {
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// ============================================
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// VOACAP / HF PROPAGATION PREDICTION API
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// IONOSONDE DATA API (Real-time ionospheric data from KC2G/GIRO)
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// ============================================
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// Cache for ionosonde data (refresh every 10 minutes)
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let ionosondeCache = {
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data: null,
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timestamp: 0,
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maxAge: 10 * 60 * 1000 // 10 minutes
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};
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// Fetch real-time ionosonde data from KC2G (GIRO network)
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async function fetchIonosondeData() {
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const now = Date.now();
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// Return cached data if fresh
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if (ionosondeCache.data && (now - ionosondeCache.timestamp) < ionosondeCache.maxAge) {
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return ionosondeCache.data;
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}
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try {
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const response = await fetch('https://prop.kc2g.com/api/stations.json', {
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headers: { 'User-Agent': 'OpenHamClock/3.5' },
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timeout: 15000
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});
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if (!response.ok) throw new Error(`HTTP ${response.status}`);
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const data = await response.json();
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// Filter to only recent data (within last 2 hours) with valid readings
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const twoHoursAgo = new Date(Date.now() - 2 * 60 * 60 * 1000);
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const validStations = data.filter(s => {
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if (!s.fof2 || !s.station) return false;
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const stationTime = new Date(s.time);
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return stationTime > twoHoursAgo && s.cs > 0; // confidence score > 0
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}).map(s => ({
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code: s.station.code,
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name: s.station.name,
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lat: parseFloat(s.station.latitude),
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lon: parseFloat(s.station.longitude) > 180 ? parseFloat(s.station.longitude) - 360 : parseFloat(s.station.longitude),
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foF2: s.fof2,
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mufd: s.mufd, // MUF at 3000km
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hmF2: s.hmf2, // Height of F2 layer
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md: parseFloat(s.md) || 3.0, // M(3000)F2 factor
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confidence: s.cs,
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time: s.time
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}));
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ionosondeCache = {
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data: validStations,
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timestamp: now
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};
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console.log(`[Ionosonde] Fetched ${validStations.length} valid stations from KC2G`);
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return validStations;
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} catch (error) {
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console.error('[Ionosonde] Fetch error:', error.message);
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return ionosondeCache.data || [];
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}
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}
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// API endpoint to get ionosonde data
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app.get('/api/ionosonde', async (req, res) => {
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try {
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const stations = await fetchIonosondeData();
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res.json({
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count: stations.length,
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timestamp: new Date().toISOString(),
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stations: stations
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});
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} catch (error) {
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console.error('[Ionosonde] API error:', error.message);
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res.status(500).json({ error: 'Failed to fetch ionosonde data' });
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}
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});
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// Calculate distance between two points in km
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function haversineDistance(lat1, lon1, lat2, lon2) {
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const R = 6371;
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const dLat = (lat2 - lat1) * Math.PI / 180;
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const dLon = (lon2 - lon1) * Math.PI / 180;
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const a = Math.sin(dLat/2) * Math.sin(dLat/2) +
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Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) *
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Math.sin(dLon/2) * Math.sin(dLon/2);
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return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
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}
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// Interpolate foF2 at a given location using inverse distance weighting
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function interpolateFoF2(lat, lon, stations) {
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if (!stations || stations.length === 0) return null;
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// Calculate distances to all stations
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const stationsWithDist = stations.map(s => ({
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...s,
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distance: haversineDistance(lat, lon, s.lat, s.lon)
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})).filter(s => s.foF2 > 0);
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if (stationsWithDist.length === 0) return null;
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// Sort by distance and take nearest 5
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stationsWithDist.sort((a, b) => a.distance - b.distance);
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const nearest = stationsWithDist.slice(0, 5);
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// If very close to a station, use its value directly
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if (nearest[0].distance < 100) {
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return {
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foF2: nearest[0].foF2,
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mufd: nearest[0].mufd,
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hmF2: nearest[0].hmF2,
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md: nearest[0].md,
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source: nearest[0].name,
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confidence: nearest[0].confidence,
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method: 'direct'
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};
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}
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// Inverse distance weighted interpolation
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let sumWeights = 0;
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let sumFoF2 = 0;
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let sumMufd = 0;
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let sumHmF2 = 0;
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let sumMd = 0;
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nearest.forEach(s => {
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const weight = (s.confidence / 100) / Math.pow(s.distance, 2);
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sumWeights += weight;
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sumFoF2 += s.foF2 * weight;
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if (s.mufd) sumMufd += s.mufd * weight;
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if (s.hmF2) sumHmF2 += s.hmF2 * weight;
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if (s.md) sumMd += s.md * weight;
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});
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return {
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foF2: sumFoF2 / sumWeights,
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mufd: sumMufd > 0 ? sumMufd / sumWeights : null,
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hmF2: sumHmF2 > 0 ? sumHmF2 / sumWeights : null,
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md: sumMd > 0 ? sumMd / sumWeights : 3.0,
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nearestStation: nearest[0].name,
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nearestDistance: Math.round(nearest[0].distance),
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stationsUsed: nearest.length,
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method: 'interpolated'
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};
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}
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// ============================================
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// ENHANCED PROPAGATION PREDICTION API (ITU-R P.533 based)
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// ============================================
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app.get('/api/propagation', async (req, res) => {
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const { deLat, deLon, dxLat, dxLon } = req.query;
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console.log('[Propagation] Calculating for DE:', deLat, deLon, 'to DX:', dxLat, dxLon);
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console.log('[Propagation] Enhanced calculation for DE:', deLat, deLon, 'to DX:', dxLat, dxLon);
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try {
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// Get current space weather data for calculations
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let sfi = 150, ssn = 100, kIndex = 2; // Defaults
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// Get current space weather data
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let sfi = 150, ssn = 100, kIndex = 2;
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try {
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const [fluxRes, kRes] = await Promise.allSettled([
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@ -810,26 +956,39 @@ app.get('/api/propagation', async (req, res) => {
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const data = await kRes.value.json();
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if (data?.length > 1) kIndex = parseInt(data[data.length - 1][1]) || 2;
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}
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// Estimate SSN from SFI: SSN ≈ (SFI - 67) / 0.97
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ssn = Math.max(0, Math.round((sfi - 67) / 0.97));
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} catch (e) {
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console.log('[Propagation] Using default solar values');
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}
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console.log('[Propagation] Solar data - SFI:', sfi, 'SSN:', ssn, 'K:', kIndex);
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// Get real ionosonde data
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const ionosondeStations = await fetchIonosondeData();
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// Calculate distance and bearing
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// Calculate path geometry
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const de = { lat: parseFloat(deLat) || 40, lon: parseFloat(deLon) || -75 };
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const dx = { lat: parseFloat(dxLat) || 35, lon: parseFloat(dxLon) || 139 };
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const distance = calculateDistance(de.lat, de.lon, dx.lat, dx.lon);
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const distance = haversineDistance(de.lat, de.lon, dx.lat, dx.lon);
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const midLat = (de.lat + dx.lat) / 2;
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let midLon = (de.lon + dx.lon) / 2;
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// Handle antimeridian crossing
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if (Math.abs(de.lon - dx.lon) > 180) {
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midLon = (de.lon + dx.lon + 360) / 2;
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if (midLon > 180) midLon -= 360;
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}
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// Get ionospheric data at path midpoint
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const ionoData = interpolateFoF2(midLat, midLon, ionosondeStations);
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console.log('[Propagation] Distance:', Math.round(distance), 'km, MidLat:', midLat.toFixed(1));
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console.log('[Propagation] Distance:', Math.round(distance), 'km');
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console.log('[Propagation] Solar: SFI', sfi, 'SSN', ssn, 'K', kIndex);
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if (ionoData) {
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console.log('[Propagation] Real foF2:', ionoData.foF2?.toFixed(2), 'MHz from', ionoData.nearestStation || ionoData.source);
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}
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// Calculate propagation for each band at each hour
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const bands = ['160m', '80m', '40m', '30m', '20m', '17m', '15m', '12m', '10m', '6m'];
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const bandFreqs = [1.8, 3.5, 7, 10, 14, 18, 21, 24, 28, 50]; // MHz
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const bandFreqs = [1.8, 3.5, 7, 10, 14, 18, 21, 24, 28, 50];
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const currentHour = new Date().getUTCHours();
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// Generate 24-hour predictions
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@ -840,8 +999,8 @@ app.get('/api/propagation', async (req, res) => {
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predictions[band] = [];
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for (let hour = 0; hour < 24; hour++) {
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const reliability = calculateBandReliability(
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freq, distance, midLat, hour, sfi, ssn, kIndex, de, dx
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const reliability = calculateEnhancedReliability(
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freq, distance, midLat, midLon, hour, sfi, ssn, kIndex, de, dx, ionoData, currentHour
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);
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predictions[band].push({
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hour,
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@ -851,7 +1010,7 @@ app.get('/api/propagation', async (req, res) => {
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}
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});
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// Get current best bands
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// Current best bands
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const currentBands = bands.map((band, idx) => ({
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band,
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freq: bandFreqs[idx],
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@ -860,12 +1019,27 @@ app.get('/api/propagation', async (req, res) => {
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status: getStatus(predictions[band][currentHour].reliability)
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})).sort((a, b) => b.reliability - a.reliability);
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// Calculate current MUF and LUF
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const currentMuf = calculateMUF(distance, midLat, midLon, currentHour, sfi, ssn, ionoData);
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const currentLuf = calculateLUF(distance, midLat, currentHour, sfi, kIndex);
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res.json({
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solarData: { sfi, ssn, kIndex },
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ionospheric: ionoData ? {
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foF2: ionoData.foF2?.toFixed(2),
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mufd: ionoData.mufd?.toFixed(1),
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hmF2: ionoData.hmF2?.toFixed(0),
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source: ionoData.nearestStation || ionoData.source,
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method: ionoData.method,
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stationsUsed: ionoData.stationsUsed || 1
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} : { source: 'model', method: 'estimated' },
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muf: Math.round(currentMuf * 10) / 10,
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luf: Math.round(currentLuf * 10) / 10,
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distance: Math.round(distance),
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currentHour,
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currentBands,
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hourlyPredictions: predictions
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hourlyPredictions: predictions,
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dataSource: ionoData ? 'KC2G/GIRO Ionosonde Network' : 'Estimated from solar indices'
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});
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} catch (error) {
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@ -874,79 +1048,180 @@ app.get('/api/propagation', async (req, res) => {
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}
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});
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// Calculate great circle distance in km
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function calculateDistance(lat1, lon1, lat2, lon2) {
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const R = 6371;
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const dLat = (lat2 - lat1) * Math.PI / 180;
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const dLon = (lon2 - lon1) * Math.PI / 180;
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const a = Math.sin(dLat/2) * Math.sin(dLat/2) +
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Math.cos(lat1 * Math.PI / 180) * Math.cos(lat2 * Math.PI / 180) *
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Math.sin(dLon/2) * Math.sin(dLon/2);
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return R * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
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// Calculate MUF using real ionosonde data or model
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function calculateMUF(distance, midLat, midLon, hour, sfi, ssn, ionoData) {
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// If we have real MUF(3000) data, scale it for actual distance
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if (ionoData?.mufd) {
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// MUF scales with distance: MUF(d) ≈ MUF(3000) * sqrt(3000/d) for d < 3000km
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// For d > 3000km, MUF(d) ≈ MUF(3000) * (1 + 0.1 * log(d/3000))
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if (distance < 3000) {
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return ionoData.mufd * Math.sqrt(distance / 3000);
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} else {
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return ionoData.mufd * (1 + 0.15 * Math.log10(distance / 3000));
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}
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}
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// If we have foF2, calculate MUF using M(3000)F2 factor
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if (ionoData?.foF2) {
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const M = ionoData.md || 3.0; // M(3000)F2 factor, typically 2.5-3.5
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const muf3000 = ionoData.foF2 * M;
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// Scale for actual distance
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if (distance < 3000) {
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return muf3000 * Math.sqrt(distance / 3000);
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} else {
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return muf3000 * (1 + 0.15 * Math.log10(distance / 3000));
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}
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}
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// Fallback: Estimate foF2 from solar indices
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// foF2 ≈ 0.9 * sqrt(SSN + 15) * diurnal_factor
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const hourFactor = 1 + 0.4 * Math.cos((hour - 14) * Math.PI / 12); // Peak at 14:00 local
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const latFactor = 1 - Math.abs(midLat) / 150; // Higher latitudes = lower foF2
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const foF2_est = 0.9 * Math.sqrt(ssn + 15) * hourFactor * latFactor;
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// Standard M(3000)F2 factor
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const M = 3.0;
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const muf3000 = foF2_est * M;
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// Scale for distance
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if (distance < 3000) {
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return muf3000 * Math.sqrt(distance / 3000);
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} else {
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return muf3000 * (1 + 0.15 * Math.log10(distance / 3000));
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}
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}
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// Calculate band reliability percentage (simplified VOACAP-style)
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function calculateBandReliability(freq, distance, midLat, hour, sfi, ssn, kIndex, de, dx) {
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// Maximum Usable Frequency estimation
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// MUF ≈ criticalFreq * secant(zenith angle) * sqrt(1 + distance/4000)
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// Calculate LUF (Lowest Usable Frequency) based on D-layer absorption
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function calculateLUF(distance, midLat, hour, sfi, kIndex) {
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// LUF increases with:
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// - Higher solar flux (more D-layer ionization)
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// - Daytime (D-layer forms during day)
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// - Shorter paths (higher elevation angles = more time in D-layer)
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// - Geomagnetic activity
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// Local solar time at midpoint (approximate)
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const localHour = hour; // Would need proper calculation with midLon
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// Day/night factor: D-layer absorption is much higher during daytime
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let dayFactor = 0.3; // Night
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if (localHour >= 6 && localHour <= 18) {
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// Daytime - peaks around noon
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dayFactor = 0.5 + 0.5 * Math.cos((localHour - 12) * Math.PI / 6);
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}
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// Solar flux factor: higher SFI = more absorption
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const sfiFactor = 1 + (sfi - 70) / 200;
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// Critical frequency varies with solar activity and time
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// foF2 ≈ 0.85 * sqrt(ssn + 12) * (1 + 0.3 * cos(hour * PI / 12))
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const hourFactor = 1 + 0.4 * Math.cos((hour - 12) * Math.PI / 12);
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const foF2 = 0.9 * Math.sqrt(ssn + 15) * hourFactor;
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// Distance factor: shorter paths have higher LUF (higher angles)
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const distFactor = Math.max(0.5, 1 - distance / 10000);
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// Distance factor (longer paths need lower angles, higher MUF)
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const distFactor = Math.sqrt(1 + distance / 3500);
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// Latitude factor: polar paths have more absorption
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const latFactor = 1 + Math.abs(midLat) / 90 * 0.5;
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// Latitude factor (higher latitudes = more absorption, lower MUF)
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const latFactor = 1 - Math.abs(midLat) / 200;
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// K-index: geomagnetic storms increase absorption
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const kFactor = 1 + kIndex * 0.1;
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// Estimated MUF
|
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|
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const muf = foF2 * distFactor * latFactor * 3.5;
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// Base LUF is around 2 MHz for long night paths
|
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|
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const baseLuf = 2.0;
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return baseLuf * dayFactor * sfiFactor * distFactor * latFactor * kFactor;
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}
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// Enhanced reliability calculation using real ionosonde data
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|
|
function calculateEnhancedReliability(freq, distance, midLat, midLon, hour, sfi, ssn, kIndex, de, dx, ionoData, currentHour) {
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// Calculate MUF and LUF for this hour
|
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|
|
// For non-current hours, we need to estimate how foF2 changes
|
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|
|
let hourIonoData = ionoData;
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|
|
if (ionoData && hour !== currentHour) {
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|
// Estimate foF2 change based on diurnal variation
|
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|
|
// foF2 typically varies by factor of 2-3 between day and night
|
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|
|
const currentHourFactor = 1 + 0.4 * Math.cos((currentHour - 14) * Math.PI / 12);
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|
|
const targetHourFactor = 1 + 0.4 * Math.cos((hour - 14) * Math.PI / 12);
|
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|
|
const scaleFactor = targetHourFactor / currentHourFactor;
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|
|
hourIonoData = {
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...ionoData,
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foF2: ionoData.foF2 * scaleFactor,
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mufd: ionoData.mufd ? ionoData.mufd * scaleFactor : null
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|
|
};
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}
|
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|
|
// Lowest Usable Frequency (absorption limit)
|
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|
|
// LUF increases with solar activity and during daytime
|
|
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|
|
const dayNight = isDaytime(hour, (de.lon + dx.lon) / 2) ? 1.5 : 0.5;
|
|
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|
|
const luf = 2 + (sfi / 100) * dayNight + kIndex * 0.5;
|
|
|
|
|
const muf = calculateMUF(distance, midLat, midLon, hour, sfi, ssn, hourIonoData);
|
|
|
|
|
const luf = calculateLUF(distance, midLat, hour, sfi, kIndex);
|
|
|
|
|
|
|
|
|
|
// Calculate reliability based on frequency vs MUF/LUF
|
|
|
|
|
// Calculate reliability based on frequency position relative to MUF/LUF
|
|
|
|
|
let reliability = 0;
|
|
|
|
|
|
|
|
|
|
if (freq > muf) {
|
|
|
|
|
// Frequency above MUF - poor propagation
|
|
|
|
|
reliability = Math.max(0, 50 - (freq - muf) * 10);
|
|
|
|
|
if (freq > muf * 1.1) {
|
|
|
|
|
// Well above MUF - very poor
|
|
|
|
|
reliability = Math.max(0, 30 - (freq - muf) * 5);
|
|
|
|
|
} else if (freq > muf) {
|
|
|
|
|
// Slightly above MUF - marginal (sometimes works due to scatter)
|
|
|
|
|
reliability = 30 + (muf * 1.1 - freq) / (muf * 0.1) * 20;
|
|
|
|
|
} else if (freq < luf * 0.8) {
|
|
|
|
|
// Well below LUF - absorbed
|
|
|
|
|
reliability = Math.max(0, 20 - (luf - freq) * 10);
|
|
|
|
|
} else if (freq < luf) {
|
|
|
|
|
// Frequency below LUF - too much absorption
|
|
|
|
|
reliability = Math.max(0, 50 - (luf - freq) * 15);
|
|
|
|
|
// Near LUF - marginal
|
|
|
|
|
reliability = 20 + (freq - luf * 0.8) / (luf * 0.2) * 30;
|
|
|
|
|
} else {
|
|
|
|
|
// Frequency in usable range
|
|
|
|
|
const midFreq = (muf + luf) / 2;
|
|
|
|
|
const optimalness = 1 - Math.abs(freq - midFreq) / (muf - luf);
|
|
|
|
|
reliability = 50 + optimalness * 45;
|
|
|
|
|
// In usable range - calculate optimum
|
|
|
|
|
// Optimum Working Frequency (OWF) is typically 80-85% of MUF
|
|
|
|
|
const owf = muf * 0.85;
|
|
|
|
|
const range = muf - luf;
|
|
|
|
|
|
|
|
|
|
if (range <= 0) {
|
|
|
|
|
reliability = 30; // Very narrow window
|
|
|
|
|
} else {
|
|
|
|
|
// Higher reliability near OWF, tapering toward MUF and LUF
|
|
|
|
|
const position = (freq - luf) / range; // 0 at LUF, 1 at MUF
|
|
|
|
|
const optimalPosition = 0.75; // 75% up from LUF = OWF
|
|
|
|
|
|
|
|
|
|
if (position < optimalPosition) {
|
|
|
|
|
// Below OWF - reliability increases as we approach OWF
|
|
|
|
|
reliability = 50 + (position / optimalPosition) * 45;
|
|
|
|
|
} else {
|
|
|
|
|
// Above OWF - reliability decreases as we approach MUF
|
|
|
|
|
reliability = 95 - ((position - optimalPosition) / (1 - optimalPosition)) * 45;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// K-index degradation (geomagnetic storms)
|
|
|
|
|
if (kIndex >= 5) reliability *= 0.3;
|
|
|
|
|
if (kIndex >= 7) reliability *= 0.1;
|
|
|
|
|
else if (kIndex >= 6) reliability *= 0.2;
|
|
|
|
|
else if (kIndex >= 5) reliability *= 0.4;
|
|
|
|
|
else if (kIndex >= 4) reliability *= 0.6;
|
|
|
|
|
else if (kIndex >= 3) reliability *= 0.8;
|
|
|
|
|
|
|
|
|
|
// Distance adjustment - very long paths are harder
|
|
|
|
|
if (distance > 15000) reliability *= 0.7;
|
|
|
|
|
else if (distance > 10000) reliability *= 0.85;
|
|
|
|
|
// Very long paths (multiple hops) are harder
|
|
|
|
|
const hops = Math.ceil(distance / 3500);
|
|
|
|
|
if (hops > 1) {
|
|
|
|
|
reliability *= Math.pow(0.92, hops - 1); // ~8% loss per additional hop
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// High bands need higher solar activity
|
|
|
|
|
if (freq >= 21 && sfi < 100) reliability *= (sfi / 100);
|
|
|
|
|
if (freq >= 28 && sfi < 120) reliability *= (sfi / 120);
|
|
|
|
|
// Polar path penalty (auroral absorption)
|
|
|
|
|
if (Math.abs(midLat) > 60) {
|
|
|
|
|
reliability *= 0.7;
|
|
|
|
|
if (kIndex >= 3) reliability *= 0.7; // Additional penalty during storms
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// High bands need sufficient solar activity
|
|
|
|
|
if (freq >= 21 && sfi < 100) reliability *= Math.sqrt(sfi / 100);
|
|
|
|
|
if (freq >= 28 && sfi < 120) reliability *= Math.sqrt(sfi / 120);
|
|
|
|
|
if (freq >= 50 && sfi < 150) reliability *= Math.pow(sfi / 150, 1.5);
|
|
|
|
|
|
|
|
|
|
// Low bands work better at night
|
|
|
|
|
const localHour = (hour + midLon / 15 + 24) % 24;
|
|
|
|
|
const isNight = localHour < 6 || localHour > 18;
|
|
|
|
|
if (freq <= 7 && isNight) reliability *= 1.1;
|
|
|
|
|
if (freq <= 3.5 && !isNight) reliability *= 0.7;
|
|
|
|
|
|
|
|
|
|
return Math.min(99, Math.max(0, reliability));
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Check if it's daytime at given longitude
|
|
|
|
|
function isDaytime(utcHour, longitude) {
|
|
|
|
|
const localHour = (utcHour + longitude / 15 + 24) % 24;
|
|
|
|
|
return localHour >= 6 && localHour <= 18;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
// Convert reliability to estimated SNR
|
|
|
|
|
function calculateSNR(reliability) {
|
|
|
|
|
if (reliability >= 80) return '+20dB';
|
|
|
|
|
|
accius
4 days ago