2025-07-17 15:33:02 +02:00

121 lines
3.9 KiB
TypeScript

import computeDestinationPoint from 'geolib/es/computeDestinationPoint';
import getGreatCircleBearing from 'geolib/es/getGreatCircleBearing';
import getPreciseDistance from 'geolib/es/getPreciseDistance';
import Parser from '../parser';
import { generateTangentArc } from '../pathGenerators/generateTangentArc';
import { computeSpeed } from '../utils/computeSpeed';
import { computeTurnRate } from '../utils/computeTurnRate';
export const TerminatorsCF = (
leg: CFTerminalEntry,
previousFix: NavFix,
lastCourse: number,
waypoint?: Waypoint
): [NavFix?, LineSegment[]?] => {
const speed = computeSpeed(leg, previousFix);
const crsIntoEndpoint = leg.Course.toTrue(previousFix);
const line: LineSegment[] = [];
const targetFix: NavFix = {
latitude: leg.WptLat,
longitude: leg.WptLon,
name: waypoint?.Ident ?? undefined,
isFlyOver: leg.IsFlyOver,
altitude: leg.Alt ? leg.Alt.parseAltitude() : previousFix.altitude,
speed: speed,
speedConstraint: leg.SpeedLimit,
altitudeConstraint: leg.Alt,
IsFAF: leg.IsFAF,
IsMAP: leg.IsMAP,
};
const crsToIntercept = leg.Course.toTrue(targetFix);
// Compute overfly arc
let arc1: LineSegment[] | null = null;
let arc2: LineSegment[] = [[previousFix.longitude, previousFix.latitude]];
if (previousFix.isFlyOver) {
arc1 = generateTangentArc(crsIntoEndpoint, lastCourse, previousFix, targetFix, leg.TurnDir);
} else {
arc1 = [[previousFix.longitude, previousFix.latitude]];
}
let arc;
if (arc1 && arc1.length > 1) {
const endCrs = getGreatCircleBearing(
{
latitude: arc1.at(-1)![1],
longitude: arc1.at(-1)![0],
},
targetFix
);
const endDist = getPreciseDistance(
{
latitude: arc1.at(-1)![1],
longitude: arc1.at(-1)![0],
},
targetFix
);
if (endDist <= 25 || (endCrs <= crsIntoEndpoint + 1 && endCrs >= crsIntoEndpoint - 1)) arc = arc1;
}
if (previousFix.isFlyOver && (!lastCourse.equal(crsIntoEndpoint) || !lastCourse.equal(crsToIntercept))) {
const turnRate = computeTurnRate(speed, Parser.AC_BANK);
let updatedCrsToIntercept = getGreatCircleBearing(previousFix, targetFix);
// Turn Dir
if (!leg.TurnDir || leg.TurnDir === 'E') {
let prov = lastCourse - crsIntoEndpoint;
prov = prov > 180 ? prov - 360 : prov <= -180 ? prov + 360 : prov;
leg.TurnDir = prov > 0 ? 'L' : 'R';
}
// Generate arc
let lastDistance = getPreciseDistance(previousFix, targetFix);
while (!updatedCrsToIntercept.equal(crsToIntercept)) {
let interceptAngle = 0;
if (leg.TurnDir === 'R') interceptAngle = Math.abs(lastCourse - crsToIntercept);
else interceptAngle = Math.abs(crsToIntercept - lastCourse);
let time = 0;
const increment = 0.1;
if (interceptAngle < 44.9 || interceptAngle >= 45.1) {
if (leg.TurnDir === 'R') {
lastCourse = (lastCourse + increment).normaliseDegrees();
time = increment / turnRate;
} else {
lastCourse = (lastCourse - increment).normaliseDegrees();
time = increment / turnRate;
}
} else time = increment / turnRate;
const arcFix = computeDestinationPoint(
{
latitude: arc2.at(-1)![1],
longitude: arc2.at(-1)![0],
},
((speed / 3600) * time).toMetre(),
lastCourse
);
arc2.push([arcFix.longitude, arcFix.latitude]);
// Update previousFix
previousFix.latitude = arcFix.latitude;
previousFix.longitude = arcFix.longitude;
updatedCrsToIntercept = getGreatCircleBearing(previousFix, targetFix);
const newDistance = getPreciseDistance(previousFix, targetFix);
if (lastDistance <= newDistance && lastDistance < 25) break;
lastDistance = newDistance;
}
}
if (!arc) arc = arc2;
line.push(...arc);
line.push([targetFix.longitude, targetFix.latitude]);
return [targetFix, line];
};