Merge pull request #108 from thkruz/sgp4Validation

Sgp4 validation

.gitignore

@@ -6,3 +6,4 @@ lib
 sgp4_verification/lib/sgp4
 *.log
 package-lock.json
+test/propagation/sgp4prop

package.json

@@ -66,6 +66,12 @@
     "rollup": "^2.26.11",
     "rollup-plugin-terser": "^7.0.2"
   },
+  "jest": {
+    "testPathIgnorePatterns": [
+      "node_modules",
+      "test/propagation/sgp4prop"
+    ]
+  },
   "homepage": "https://github.com/shashwatak/satellite-js",
   "directories": {
     "lib": "lib",

src/constants.js

@@ -3,13 +3,13 @@ export const twoPi = pi * 2;
 export const deg2rad = pi / 180.0;
 export const rad2deg = 180 / pi;
 export const minutesPerDay = 1440.0;
-export const mu = 398600.5; // in km3 / s2
-export const earthRadius = 6378.137; // in km
+export const mu = 398600.8; // in km3 / s2
+export const earthRadius = 6378.135; // in km
 export const xke = 60.0 / Math.sqrt((earthRadius * earthRadius * earthRadius) / mu);
 export const vkmpersec = (earthRadius * xke) / 60.0;
 export const tumin = 1.0 / xke;
-export const j2 = 0.00108262998905;
-export const j3 = -0.00000253215306;
-export const j4 = -0.00000161098761;
+export const j2 = 0.001082616;
+export const j3 = -0.00000253881;
+export const j4 = -0.00000165597;
 export const j3oj2 = j3 / j2;
 export const x2o3 = 2.0 / 3.0;

src/io.js

@@ -1,13 +1,6 @@
-import {
-  pi,
-  tumin,
-  deg2rad,
-} from './constants';
+import { pi, deg2rad } from './constants';
 
-import {
-  jday,
-  days2mdhms,
-} from './ext';
+import { jday, days2mdhms } from './ext';
 
 import sgp4init from './propagation/sgp4init';
 
@@ -80,13 +73,16 @@ export default function twoline2satrec(longstr1, longstr2) {
   satrec.epochdays = parseFloat(longstr1.substring(20, 32));
   satrec.ndot = parseFloat(longstr1.substring(33, 43));
   satrec.nddot = parseFloat(
-    `.${parseInt(longstr1.substring(44, 50), 10)
-    }E${longstr1.substring(50, 52)}`,
+    `.${parseInt(longstr1.substring(44, 50), 10)}E${longstr1.substring(
+      50,
+      52,
+    )}`,
   );
   satrec.bstar = parseFloat(
-    `${longstr1.substring(53, 54)
-    }.${parseInt(longstr1.substring(54, 59), 10)
-    }E${longstr1.substring(59, 61)}`,
+    `${longstr1.substring(53, 54)}.${parseInt(
+      longstr1.substring(54, 59),
+      10,
+    )}E${longstr1.substring(59, 61)}`,
   );
 
   // satrec.satnum = longstr2.substring(2, 7);
@@ -103,19 +99,15 @@ export default function twoline2satrec(longstr1, longstr2) {
   // satrec.bstar= satrec.bstar * Math.pow(10.0, ibexp);
 
   // ---- convert to sgp4 units ----
-  satrec.a = ((satrec.no * tumin) ** (-2.0 / 3.0));
-  satrec.ndot /= (xpdotp * 1440.0); // ? * minperday
-  satrec.nddot /= (xpdotp * 1440.0 * 1440);
+  // satrec.ndot /= (xpdotp * 1440.0); // ? * minperday
+  // satrec.nddot /= (xpdotp * 1440.0 * 1440);
 
   // ---- find standard orbital elements ----
   satrec.inclo *= deg2rad;
   satrec.nodeo *= deg2rad;
   satrec.argpo *= deg2rad;
   satrec.mo *= deg2rad;
 
-  satrec.alta = (satrec.a * (1.0 + satrec.ecco)) - 1.0;
-  satrec.altp = (satrec.a * (1.0 - satrec.ecco)) - 1.0;
-
   // ----------------------------------------------------------------
   // find sgp4epoch time of element set
   // remember that sgp4 uses units of days from 0 jan 1950 (sgp4epoch)
@@ -134,11 +126,7 @@ export default function twoline2satrec(longstr1, longstr2) {
   const mdhmsResult = days2mdhms(year, satrec.epochdays);
 
   const {
-    mon,
-    day,
-    hr,
-    minute,
-    sec,
+    mon, day, hr, minute, sec,
   } = mdhmsResult;
   satrec.jdsatepoch = jday(year, mon, day, hr, minute, sec);
 

src/propagation/dspace.js

@@ -215,10 +215,10 @@ export default function dspace(options) {
           + (d3222 * Math.cos((-xomi + xli) - g32))
           + (d5220 * Math.cos((xomi + xli) - g52))
           + (d5232 * Math.cos((-xomi + xli) - g52))
-          + (2.0 * d4410 * Math.cos((x2omi + x2li) - g44))
+          + 2.0 * ((d4410 * Math.cos((x2omi + x2li) - g44))
           + (d4422 * Math.cos(x2li - g44))
           + (d5421 * Math.cos((xomi + x2li) - g54))
-          + (d5433 * Math.cos((-xomi + x2li) - g54));
+          + (d5433 * Math.cos((-xomi + x2li) - g54)));
         xnddt *= xldot;
       }
 

src/propagation/sgp4init.js

@@ -5,6 +5,7 @@ import {
   j4,
   j3oj2,
   x2o3,
+  tumin,
 } from '../constants';
 
 import dpper from './dpper';
@@ -262,6 +263,9 @@ export default function sgp4init(satrec, options) {
   satrec.no = initlResult.no;
   satrec.con41 = initlResult.con41;
   satrec.gsto = initlResult.gsto;
+  satrec.a = (satrec.no * tumin) ** (-2.0 / 3.0);
+  satrec.alta = satrec.a * (1.0 + satrec.ecco) - 1.0;
+  satrec.altp = satrec.a * (1.0 - satrec.ecco) - 1.0;
   satrec.error = 0;
 
   // sgp4fix remove this check as it is unnecessary

test/propagation/dsinit.json

@@ -78,16 +78,16 @@
     "results": {
       "argpm": 0,
       "atime": 0,
-      "d2201": -1.2099452515548102e-11,
-      "d2211": 1.0011506195793891e-11,
-      "d3210": -5.0866898135037016e-12,
-      "d3222": -3.987984720569471e-13,
-      "d4410": 4.109492519702797e-13,
-      "d4422": 9.349618846253649e-14,
-      "d5220": 2.4097891471717693e-13,
-      "d5232": 1.6478793629942387e-13,
-      "d5421": -2.138743302011661e-13,
-      "d5433": -9.311246040525512e-15,
+      "d2201": -1.2099438856510436e-11,
+      "d2211": 1.0011494893832913e-11,
+      "d3210": -5.086681199981555e-12,
+      "d3222": -3.9879779675343986e-13,
+      "d4410": 4.10948324131911e-13,
+      "d4422": 9.349597736749112e-14,
+      "d5220": 2.4097823461671757e-13,
+      "d5232": 1.6478747122823163e-13,
+      "d5421": -2.1387372659636362e-13,
+      "d5433": -9.311219761949575e-15,
       "dedt": 6.387624124699951e-9,
       "del1": 0,
       "del2": 0,
@@ -188,16 +188,16 @@
     "results": {
       "argpm": 0,
       "atime": 0,
-      "d2201": -2.077924583398718e-11,
-      "d2211": 8.354983905797916e-11,
-      "d3210": -7.971726821781479e-11,
-      "d3222": -1.5879590871766552e-11,
-      "d4410": 1.5757473446619235e-11,
-      "d4422": 7.56870174312408e-12,
-      "d5220": 3.642170086460131e-11,
-      "d5232": 6.090615241770774e-11,
-      "d5421": -4.636788210900563e-11,
-      "d5433": -5.740340181834411e-12,
+      "d2201": -2.077922237635543e-11,
+      "d2211": 8.354974473880257e-11,
+      "d3210": -7.971713322895552e-11,
+      "d3222": -1.5879563982136425e-11,
+      "d4410": 1.575743786950506e-11,
+      "d4422": 7.56868465456182e-12,
+      "d5220": 3.642159807380104e-11,
+      "d5232": 6.0905980525896e-11,
+      "d5421": -4.636775124768956e-11,
+      "d5433": -5.740323981213709e-12,
       "dedt": 5.789849295568645e-9,
       "del1": 0,
       "del2": 0,

test/propagation/full-catalog/BadTLE.txt

@@ -0,0 +1,20 @@
+1 33589U 91003S   19156.28428763 -.00000001 +00000-0 +39291-2 0  9991
+2 33589 007.5114 000.3168 6752729 232.4889 045.0370 02.63585777043792
+1 40081U 14038C   22221.24935965 -.00000020  00000-0  00000-0 0  9994
+2 40081   0.0544   0.3980 0002696 138.3497 221.2709  5.00115359147392
+
+// Reentry
+1 50643U 82092AMP 22107.08250619  .17935521 -11960-5  45096-2 0  9994
+2 50643  82.5475 328.5319 0011741 236.4515 123.5658 16.28849345 21342
+
+// Crazy Ecce
+1 43846U 18103B   22079.42598936 -.00047618  00000-0  00000-0 0  9991
+2 43846  55.1662   7.8333 7551453  59.2451  33.0956  0.02456857158065
+1 48419U 91075Q   22221.28029576  .00000566  00000-0  14123-2 0  9996
+2 48419   7.5076   0.1398 6425379  73.0041 344.7415  3.27664205103484
+
+// Huge B*
+1 44850U 19088A   22221.48313072 -.00000011  00000-0  16595+1 0  9993
+2 44850  64.9641 120.9119 0012532 260.4965 279.9784  2.13102398 20705
+1 89400U          22135.70173143 -.00029463 +00000+0 -45712+1 0  9994
+2 89400  63.1733 251.3371 1951966 101.2335 281.1876  8.12027678    15