2025-07-17 20:57:12 +02:00

89 lines
2.7 KiB
TypeScript

import computeDestinationPoint from 'geolib/es/computeDestinationPoint';
import Parser from '../parser';
import { computeSpeed } from '../utils/computeSpeed';
import { computeTurnRate } from '../utils/computeTurnRate';
// NOTE: Distance is interpreted as distance and not time
export const TerminatorsHA = (leg: HATerminalEntry, previousFix: NavFix): [NavFix?, LineSegment[]?] => {
const refFix = {
latitude: leg.WptLat,
longitude: leg.WptLon,
};
const speed = computeSpeed(leg, previousFix);
const turnRate = computeTurnRate(speed, Parser.AC_BANK);
const inboundCrs = leg.Course.toTrue(refFix);
const outboundCrs = inboundCrs.reciprocalCourse();
const line: LineSegment[] = [[previousFix.longitude, previousFix.latitude]];
// Generate top arc
let currentCrs = inboundCrs;
while (!currentCrs.equal(outboundCrs)) {
let time = 0;
if (leg.TurnDir === 'R') {
const delta = (outboundCrs - currentCrs).normaliseDegrees();
const increment = delta < 0.1 ? delta : 0.1;
currentCrs = (currentCrs + increment).normaliseDegrees();
time = increment / turnRate;
} else {
const delta = (currentCrs - outboundCrs).normaliseDegrees();
const increment = delta < 0.1 ? delta : 0.1;
currentCrs = (currentCrs - increment).normaliseDegrees();
time = increment / turnRate;
}
const arcFix = computeDestinationPoint(
{
latitude: line.at(-1)![1],
longitude: line.at(-1)![0],
},
((speed / 3600) * time).toMetre(),
currentCrs
);
line.push([arcFix.longitude, arcFix.latitude]);
}
const outboundStart = computeDestinationPoint(
{
latitude: line.at(-1)![1],
longitude: line.at(-1)![0],
},
leg.Distance.toMetre(),
outboundCrs
);
line.push([outboundStart.longitude, outboundStart.latitude]);
// Generate bottom arc
currentCrs = outboundCrs;
while (!currentCrs.equal(inboundCrs)) {
let time = 0;
if (leg.TurnDir === 'R') {
const delta = (inboundCrs - currentCrs).normaliseDegrees();
const increment = delta < 0.1 ? delta : 0.1;
currentCrs = (currentCrs + increment).normaliseDegrees();
time = increment / turnRate;
} else {
const delta = (currentCrs - inboundCrs).normaliseDegrees();
const increment = delta < 0.1 ? delta : 0.1;
currentCrs = (currentCrs - increment).normaliseDegrees();
time = increment / turnRate;
}
const arcFix = computeDestinationPoint(
{
latitude: line.at(-1)![1],
longitude: line.at(-1)![0],
},
((speed / 3600) * time).toMetre(),
currentCrs
);
line.push([arcFix.longitude, arcFix.latitude]);
}
line.push([refFix.longitude, refFix.latitude]);
return [refFix, line];
};