init

2026-10-21 19:32:02 -04:00
commit b74d278c8e
96 changed files with 54476 additions and 0 deletions
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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.degreesLat = degreesLat;
+exports.degreesLong = degreesLong;
+exports.degreesToRadians = degreesToRadians;
+exports.ecfToEci = ecfToEci;
+exports.ecfToLookAngles = ecfToLookAngles;
+exports.eciToEcf = eciToEcf;
+exports.eciToGeodetic = eciToGeodetic;
+exports.geodeticToEcf = geodeticToEcf;
+exports.radiansLat = radiansLat;
+exports.radiansLong = radiansLong;
+exports.radiansToDegrees = radiansToDegrees;
+var _constants = require("./constants");
+function radiansToDegrees(radians) {
+  return radians * _constants.rad2deg;
+}
+function degreesToRadians(degrees) {
+  return degrees * _constants.deg2rad;
+}
+function degreesLat(radians) {
+  if (radians < -_constants.pi / 2 || radians > _constants.pi / 2) {
+    throw new RangeError('Latitude radians must be in range [-pi/2; pi/2].');
+  }
+  return radiansToDegrees(radians);
+}
+function degreesLong(radians) {
+  if (radians < -_constants.pi || radians > _constants.pi) {
+    throw new RangeError('Longitude radians must be in range [-pi; pi].');
+  }
+  return radiansToDegrees(radians);
+}
+function radiansLat(degrees) {
+  if (degrees < -90 || degrees > 90) {
+    throw new RangeError('Latitude degrees must be in range [-90; 90].');
+  }
+  return degreesToRadians(degrees);
+}
+function radiansLong(degrees) {
+  if (degrees < -180 || degrees > 180) {
+    throw new RangeError('Longitude degrees must be in range [-180; 180].');
+  }
+  return degreesToRadians(degrees);
+}
+function geodeticToEcf(_ref) {
+  var longitude = _ref.longitude,
+    latitude = _ref.latitude,
+    height = _ref.height;
+  var a = 6378.137;
+  var b = 6356.7523142;
+  var f = (a - b) / a;
+  var e2 = 2 * f - f * f;
+  var normal = a / Math.sqrt(1 - e2 * (Math.sin(latitude) * Math.sin(latitude)));
+  var x = (normal + height) * Math.cos(latitude) * Math.cos(longitude);
+  var y = (normal + height) * Math.cos(latitude) * Math.sin(longitude);
+  var z = (normal * (1 - e2) + height) * Math.sin(latitude);
+  return {
+    x: x,
+    y: y,
+    z: z
+  };
+}
+function eciToGeodetic(eci, gmst) {
+  // http://www.celestrak.com/columns/v02n03/
+  var a = 6378.137;
+  var b = 6356.7523142;
+  var R = Math.sqrt(eci.x * eci.x + eci.y * eci.y);
+  var f = (a - b) / a;
+  var e2 = 2 * f - f * f;
+  var longitude = Math.atan2(eci.y, eci.x) - gmst;
+  while (longitude < -_constants.pi) {
+    longitude += _constants.twoPi;
+  }
+  while (longitude > _constants.pi) {
+    longitude -= _constants.twoPi;
+  }
+  var kmax = 20;
+  var k = 0;
+  var latitude = Math.atan2(eci.z, Math.sqrt(eci.x * eci.x + eci.y * eci.y));
+  var C;
+  while (k++ < kmax) {
+    C = 1 / Math.sqrt(1 - e2 * (Math.sin(latitude) * Math.sin(latitude)));
+    latitude = Math.atan2(eci.z + a * C * e2 * Math.sin(latitude), R);
+  }
+  var height = R / Math.cos(latitude) - a * C;
+  return {
+    longitude: longitude,
+    latitude: latitude,
+    height: height
+  };
+}
+function ecfToEci(ecf, gmst) {
+  // ccar.colorado.edu/ASEN5070/handouts/coordsys.doc
+  //
+  // [X]     [C -S  0][X]
+  // [Y]  =  [S  C  0][Y]
+  // [Z]eci  [0  0  1][Z]ecf
+  //
+  var X = ecf.x * Math.cos(gmst) - ecf.y * Math.sin(gmst);
+  var Y = ecf.x * Math.sin(gmst) + ecf.y * Math.cos(gmst);
+  var Z = ecf.z;
+  return {
+    x: X,
+    y: Y,
+    z: Z
+  };
+}
+function eciToEcf(eci, gmst) {
+  // ccar.colorado.edu/ASEN5070/handouts/coordsys.doc
+  //
+  // [X]     [C -S  0][X]
+  // [Y]  =  [S  C  0][Y]
+  // [Z]eci  [0  0  1][Z]ecf
+  //
+  //
+  // Inverse:
+  // [X]     [C  S  0][X]
+  // [Y]  =  [-S C  0][Y]
+  // [Z]ecf  [0  0  1][Z]eci
+  var x = eci.x * Math.cos(gmst) + eci.y * Math.sin(gmst);
+  var y = eci.x * -Math.sin(gmst) + eci.y * Math.cos(gmst);
+  var z = eci.z;
+  return {
+    x: x,
+    y: y,
+    z: z
+  };
+}
+function topocentric(observerGeodetic, satelliteEcf) {
+  // http://www.celestrak.com/columns/v02n02/
+  // TS Kelso's method, except I'm using ECF frame
+  // and he uses ECI.
+  var longitude = observerGeodetic.longitude,
+    latitude = observerGeodetic.latitude;
+  var observerEcf = geodeticToEcf(observerGeodetic);
+  var rx = satelliteEcf.x - observerEcf.x;
+  var ry = satelliteEcf.y - observerEcf.y;
+  var rz = satelliteEcf.z - observerEcf.z;
+  var topS = Math.sin(latitude) * Math.cos(longitude) * rx + Math.sin(latitude) * Math.sin(longitude) * ry - Math.cos(latitude) * rz;
+  var topE = -Math.sin(longitude) * rx + Math.cos(longitude) * ry;
+  var topZ = Math.cos(latitude) * Math.cos(longitude) * rx + Math.cos(latitude) * Math.sin(longitude) * ry + Math.sin(latitude) * rz;
+  return {
+    topS: topS,
+    topE: topE,
+    topZ: topZ
+  };
+}
+function topocentricToLookAngles(tc) {
+  var topS = tc.topS,
+    topE = tc.topE,
+    topZ = tc.topZ;
+  var rangeSat = Math.sqrt(topS * topS + topE * topE + topZ * topZ);
+  var El = Math.asin(topZ / rangeSat);
+  var Az = Math.atan2(-topE, topS) + _constants.pi;
+  return {
+    azimuth: Az,
+    elevation: El,
+    rangeSat: rangeSat // Range in km
+  };
+}
+function ecfToLookAngles(observerGeodetic, satelliteEcf) {
+  var topocentricCoords = topocentric(observerGeodetic, satelliteEcf);
+  return topocentricToLookAngles(topocentricCoords);
+}