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Fix aircraft categorization misclassifying Cessnas as helicopters

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N-prefix callsigns (US general aviation) were incorrectly matching the
helicopter detection rules due to 'N' in the helicopter callsign list
and a broken .some() condition. Speed/altitude heuristics were also too
broad, and zero-value speed data (not yet received) triggered false
matches. Types are now re-evaluated as better data arrives instead of
being locked to the first guess.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
root
2026-06-08 09:00:15 -07:00
parent da188ea290
commit ed4397b21b
1 changed files with 76 additions and 40 deletions
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ads-bit.js
+71 -35
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@@ -749,8 +749,9 @@ class ADSBit {
flights.forEach(flight => {
if (flight.lat && flight.lon && flight.altitude) {
this.flights.set(flight.icao, flight);
// Categorize aircraft type if not already done
if (!this.aircraftTypes.has(flight.icao)) {
// Categorize aircraft type - re-evaluate when speed data arrives
// since early messages often lack speed, leading to wrong guesses
if (!this.aircraftTypes.has(flight.icao) || (flight.speed > 0 && flight.callsign)) {
this.categorizeAircraft(flight);
}
}
@@ -760,58 +761,93 @@ class ADSBit {
categorizeAircraft(flight) {
// Categorize aircraft based on available data
// Priority: 1. Helicopter detection, 2. Callsign patterns, 3. Altitude/Speed heuristics
// Priority: 1. Callsign-based, 2. Altitude/Speed heuristics, 3. Default
//
// NOTE: speed=0 or altitude=0 means data not yet received, so we
// avoid making assumptions from missing data. The caller should
// re-categorize once better data arrives.
let category = 'narrowBody'; // Default
const callsign = (flight.callsign || '').trim();
const altitude = flight.altitude || 0;
const speed = flight.speed || 0;
const hasSpeed = speed > 0;
const hasAlt = altitude > 0;
// Helicopter detection with multiple criteria
// Known helicopter callsign patterns (medical, news, police, tours, etc.)
const helicopterCallsigns = ['LIFE', 'MED', 'STAR', 'AIR', 'CARE', 'MERCY', 'REACH', 'CHP', 'COPTER', 'HELO', 'N', 'PHI'];
const isHelicopterCallsign = helicopterCallsigns.some(pattern =>
callsign.includes(pattern) || callsign.startsWith('N') && callsign.length <= 6
);
// --- Callsign-based detection (most reliable) ---
const airline = callsign.length >= 3 ? callsign.substring(0, 3) : '';
// Helicopter speed/altitude heuristics:
// - Very low speed at any altitude (< 100 knots)
// - Low altitude with moderate speed (< 3000 ft and < 180 knots)
// - Known helicopter callsign with reasonable parameters (< 10000 ft and < 200 knots)
if (isHelicopterCallsign && altitude < 10000 && speed < 200) {
category = 'helicopter';
} else if (speed < 100 && altitude < 15000) {
category = 'helicopter';
} else if (altitude < 3000 && speed < 180) {
// Known helicopter operator callsign prefixes
const heliOperators = ['LFE', 'MED', 'CHP', 'PHI', 'ERA', 'BHS'];
// Keywords that appear anywhere in helicopter callsigns
const heliKeywords = ['LIFE', 'MERCY', 'REACH', 'COPTER', 'HELO', 'MEDEVAC', 'CARE'];
const isHeliCallsign = heliOperators.includes(airline) ||
heliKeywords.some(kw => callsign.includes(kw));
const heavyCallsigns = ['CPA', 'UAE', 'ETH', 'QTR', 'SIA', 'KLM', 'AFL', 'BAW', 'AAL', 'DAL', 'UAL', 'FDX', 'UPS'];
const regionalCallsigns = ['SKW', 'RPA', 'ASH', 'PDT', 'CHQ', 'ENY', 'JIA', 'CPZ'];
// N-number = US general aviation registration (Cessna, Piper, etc.)
const isNNumber = callsign.startsWith('N') && callsign.length >= 4 && callsign.length <= 6 && /^N\d/.test(callsign);
// --- Apply rules ---
// 1. Helicopter: callsign match + reasonable flight envelope
if (isHeliCallsign) {
category = 'helicopter';
}
// Heavy/jumbo aircraft callsigns (cargo and passenger)
else if (callsign.length > 0) {
const heavyCallsigns = ['CPA', 'UAE', 'ETH', 'QTR', 'SIA', 'KLM', 'AFL', 'BAW', 'AAL', 'DAL', 'UAL', 'FDX', 'UPS'];
// Regional jet callsigns
const regionalCallsigns = ['SKW', 'RPA', 'ASH', 'PDT', 'CHQ', 'ENY'];
// Small prop patterns (typically GA aircraft with N-numbers or short callsigns)
const isSmallProp = callsign.length <= 4 && (callsign.startsWith('N') || !callsign.match(/[0-9]/));
// Check callsign patterns
const airline = callsign.substring(0, 3);
if (heavyCallsigns.includes(airline) || altitude > 40000 || speed > 500) {
// High altitude or speed suggests wide body or heavy
if (altitude > 42000 || speed > 550) {
// 2. Heavy / Wide body
else if (heavyCallsigns.includes(airline)) {
category = (hasAlt && altitude > 42000) || (hasSpeed && speed > 550) ? 'heavy' : 'wideBody';
}
else if ((hasAlt && altitude > 42000) || (hasSpeed && speed > 550)) {
category = 'heavy';
} else {
}
else if ((hasAlt && altitude > 40000) || (hasSpeed && speed > 500)) {
category = 'wideBody';
}
} else if (regionalCallsigns.includes(airline) || (altitude < 25000 && speed < 350)) {
// 3. N-number = general aviation (small prop unless data says otherwise)
else if (isNNumber) {
// N-numbers at high altitude/speed are likely turboprops or light jets
if (hasAlt && altitude > 25000) {
category = 'narrowBody';
} else {
category = 'smallProp';
}
}
// 4. Regional jets
else if (regionalCallsigns.includes(airline)) {
category = 'regionalJet';
} else if (isSmallProp || (altitude < 10000 && speed < 200)) {
}
// 5. Speed/altitude heuristics (only when we have real data)
else if (hasSpeed && hasAlt) {
if (speed < 60 && altitude < 5000) {
// Very slow + very low = likely helicopter
category = 'helicopter';
} else if (altitude < 18000 && speed < 300) {
// Below FL180 at moderate speed
if (speed < 170 && altitude < 12000) {
category = 'smallProp';
} else {
// Default narrow body (737, A320 family)
category = 'regionalJet';
}
} else {
category = 'narrowBody';
}
}
// 6. Altitude-only heuristic
else if (hasAlt && !hasSpeed) {
if (altitude < 10000) {
category = 'smallProp'; // Low altitude, unknown speed - guess GA
} else if (altitude < 25000) {
category = 'regionalJet';
} else {
category = 'narrowBody';
}
}
// 7. No useful data yet - stay with default
// (will be re-categorized on next update)
this.aircraftTypes.set(flight.icao, category);
}