fix: 🐛 fix bug with timezone differences

thkruz · Jul 29, 2022 · d796c65 · d796c65
1 parent ca8d898
commit d796c65
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Showing 3 changed files with 17 additions and 10 deletions.
diff --git a/src/utils/sun-math.ts b/src/utils/sun-math.ts
@@ -430,8 +430,11 @@ export class SunMath {
    */
   static getSolarTime(date: Date, utcOffset: number, lon: number) {
     // calculate the day of year
-    const start = new Date(date.getFullYear(), 0, 0);
-    const diff = date.getTime() - start.getTime() + (start.getTimezoneOffset() - date.getTimezoneOffset()) * 60 * 1000;
+    const start = new Date();
+
+    start.setUTCFullYear(date.getUTCFullYear(), 0, 1);
+    start.setUTCHours(0, 0, 0, 0);
+    const diff = date.getTime() - start.getTime();
     const dayOfYear = Math.floor(diff / MS_PER_DAY);
 
     const b = (360 / 365) * (dayOfYear - 81) * DEG2RAD;

diff --git a/test/sat/sat.test.js b/test/sat/sat.test.js
@@ -6,6 +6,8 @@
 
 import { Sat, Sensor } from '../../lib/ootk';
 
+const dateObj = new Date(1661400000000);
+
 const tle1 = '1 25544U 98067A   22203.46960946  .00003068  00000+0  61583-4 0  9996';
 const tle2 = '2 25544  51.6415 161.8339 0005168  35.9781  54.7009 15.50067047350657';
 
@@ -24,7 +26,7 @@ describe('Basic Satellite functionality', () => {
   });
 
   it('should allow chaining', () => {
-    const eci = new Sat({ name: 'Test', tle1, tle2 }).propagateTo(new Date(2022, 7, 25)).getEci();
+    const eci = new Sat({ name: 'Test', tle1, tle2 }).propagateTo(dateObj).getEci();
 
     expect(eci.x).toBeCloseTo(6512.640035319078);
     expect(eci.y).toBeCloseTo(-1545.524934684146);
@@ -34,7 +36,7 @@ describe('Basic Satellite functionality', () => {
   it('should allow getting eci coordinates', () => {
     const sat = new Sat({ name: 'Test', tle1, tle2 });
 
-    const eci = sat.getEci(new Date(2022, 7, 25));
+    const eci = sat.getEci(dateObj);
 
     expect(eci.x).toBeCloseTo(6512.640035319078);
     expect(eci.y).toBeCloseTo(-1545.524934684146);
@@ -44,7 +46,7 @@ describe('Basic Satellite functionality', () => {
   it('should allow getting ecf coordinates', () => {
     const sat = new Sat({ name: 'Test', tle1, tle2 });
 
-    const eci = sat.getEcf(new Date(2022, 7, 25));
+    const eci = sat.getEcf(dateObj);
 
     expect(eci.x).toBeCloseTo(4585.677469309576);
     expect(eci.y).toBeCloseTo(-4875.929624270418);
@@ -54,7 +56,7 @@ describe('Basic Satellite functionality', () => {
   it('should allow getting lla coordinates', () => {
     const sat = new Sat({ name: 'Test', tle1, tle2 });
 
-    const eci = sat.getLla(new Date(2022, 7, 25));
+    const eci = sat.getLla(dateObj);
 
     expect(eci.lat).toBeCloseTo(-0.17779469476167792);
     expect(eci.lon).toBeCloseTo(-0.8160653803347542);
@@ -71,7 +73,7 @@ describe('Basic Satellite functionality', () => {
     const sat = new Sat({ name: 'Test', tle1, tle2 });
     const sensor = new Sensor({ name: 'Test', lat: 41, lon: -71, alt: 0 });
 
-    const rae = sat.getRae(sensor, new Date(2022, 7, 25));
+    const rae = sat.getRae(sensor, dateObj);
 
     rae.az *= RAD2DEG;
     rae.el *= RAD2DEG;
@@ -80,7 +82,7 @@ describe('Basic Satellite functionality', () => {
     expect(rae.el).toBeCloseTo(-56.89115262874271);
     expect(rae.rng).toBeCloseTo(11183.206102756607);
 
-    const rae2 = sensor.getRae(sat, new Date(2022, 7, 25));
+    const rae2 = sensor.getRae(sat, dateObj);
 
     rae2.az *= RAD2DEG;
     rae2.el *= RAD2DEG;

diff --git a/test/sun-moon/sun-moon.test.js b/test/sun-moon/sun-moon.test.js
@@ -7,7 +7,8 @@
 import { Utils } from '../../lib/ootk';
 
 const { SunMath, MoonMath } = Utils;
-const dateObj = new Date(2022, 7, 25);
+// Use number of milliseconds since epoch instead of local year, month, day, etc for consistency across machines
+const dateObj = new Date(1661400000000);
 
 describe('Sun and Moon', () => {
   test('SunMath Unit Tests', () => {
@@ -19,7 +20,8 @@ describe('Sun and Moon', () => {
   });
 
   test('Local Solar Time', () => {
-    const lst = SunMath.getSolarTime(new Date(2022, 6, 25, 23, 58), -5, -71);
+    // Use number of milliseconds since epoch instead of local year, month, day, etc for consistency across machines
+    const lst = SunMath.getSolarTime(new Date(1658807880000), -5, -71);
 
     expect(lst.toUTCString()).toEqual('Tue, 26 Jul 2022 04:07:49 GMT');
   });