1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 package org.orekit.propagation.events;
18
19 import org.hipparchus.geometry.euclidean.threed.Rotation;
20 import org.hipparchus.geometry.euclidean.threed.Vector3D;
21 import org.hipparchus.geometry.spherical.twod.Edge;
22 import org.hipparchus.ode.events.Action;
23 import org.hipparchus.util.FastMath;
24 import org.hipparchus.util.MathUtils;
25 import org.junit.jupiter.api.Assertions;
26 import org.junit.jupiter.api.BeforeEach;
27 import org.junit.jupiter.api.Test;
28 import org.orekit.Utils;
29 import org.orekit.attitudes.AttitudeProvider;
30 import org.orekit.attitudes.BodyCenterPointing;
31 import org.orekit.attitudes.NadirPointing;
32 import org.orekit.bodies.BodyShape;
33 import org.orekit.bodies.CelestialBodyFactory;
34 import org.orekit.bodies.GeodeticPoint;
35 import org.orekit.bodies.OneAxisEllipsoid;
36 import org.orekit.errors.OrekitException;
37 import org.orekit.frames.Frame;
38 import org.orekit.frames.FramesFactory;
39 import org.orekit.frames.TopocentricFrame;
40 import org.orekit.geometry.fov.CircularFieldOfView;
41 import org.orekit.geometry.fov.DoubleDihedraFieldOfView;
42 import org.orekit.geometry.fov.EllipticalFieldOfView;
43 import org.orekit.geometry.fov.FieldOfView;
44 import org.orekit.geometry.fov.PolygonalFieldOfView;
45 import org.orekit.geometry.fov.PolygonalFieldOfView.DefiningConeType;
46 import org.orekit.orbits.EquinoctialOrbit;
47 import org.orekit.orbits.KeplerianOrbit;
48 import org.orekit.orbits.Orbit;
49 import org.orekit.orbits.PositionAngleType;
50 import org.orekit.propagation.Propagator;
51 import org.orekit.propagation.SpacecraftState;
52 import org.orekit.propagation.analytical.KeplerianPropagator;
53 import org.orekit.propagation.events.EventsLogger.LoggedEvent;
54 import org.orekit.propagation.events.handlers.ContinueOnEvent;
55 import org.orekit.propagation.events.handlers.EventHandler;
56 import org.orekit.time.AbsoluteDate;
57 import org.orekit.time.DateComponents;
58 import org.orekit.time.TimeComponents;
59 import org.orekit.time.TimeScale;
60 import org.orekit.time.TimeScalesFactory;
61 import org.orekit.utils.Constants;
62 import org.orekit.utils.IERSConventions;
63 import org.orekit.utils.PVCoordinates;
64 import org.orekit.utils.PVCoordinatesProvider;
65
66 import java.util.ArrayList;
67 import java.util.List;
68
69 public class FieldOfViewDetectorTest {
70
71
72 private double mu;
73
74
75 private AbsoluteDate initDate;
76
77
78 private Orbit initialOrbit;
79
80
81 private OneAxisEllipsoid earth;
82
83
84 private BodyCenterPointing earthCenterAttitudeLaw;
85
86
87 private TimeScale utc;
88
89 @Test
90 public void testDihedralFielOfView() {
91
92
93
94
95
96 KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit, earthCenterAttitudeLaw);
97
98
99 final double halfAperture = FastMath.toRadians(0.5 * 68.0);
100 final double maxCheck = 60.;
101 final double threshold = 1.0e-10;
102 final PVCoordinatesProvider sunPV = CelestialBodyFactory.getSun();
103 final Vector3D center = Vector3D.PLUS_I;
104 final Vector3D axis1 = Vector3D.PLUS_K;
105 final Vector3D axis2 = Vector3D.PLUS_J;
106 final double aperture1 = halfAperture;
107 final double aperture2 = halfAperture;
108
109 final EventDetector sunVisi =
110 new FieldOfViewDetector(sunPV, new DoubleDihedraFieldOfView(center, axis1, aperture1, axis2, aperture2, 0.0)).
111 withMaxCheck(maxCheck).
112 withThreshold(threshold).
113 withHandler(new DihedralSunVisiHandler());
114
115 Assertions.assertSame(sunPV, ((FieldOfViewDetector) sunVisi).getPVTarget());
116 Assertions.assertEquals(0, ((FieldOfViewDetector) sunVisi).getFOV().getMargin(), 1.0e-15);
117 double eta = FastMath.acos(FastMath.sin(aperture1) * FastMath.sin(aperture2));
118 double theoreticalArea = MathUtils.TWO_PI - 4 * eta;
119 Assertions.assertEquals(theoreticalArea,
120 ((PolygonalFieldOfView) ((FieldOfViewDetector) sunVisi).getFOV()).getZone().getSize(),
121 1.0e-15);
122
123
124 EventsLogger logger = new EventsLogger();
125 propagator.addEventDetector(logger.monitorDetector(sunVisi));
126
127
128 propagator.propagate(initDate.shiftedBy(6000.));
129
130
131
132
133
134 final AbsoluteDate tA = new AbsoluteDate("1969-08-28T00:04:50.540686", utc);
135 final AbsoluteDate tB = new AbsoluteDate("1969-08-28T00:08:08.299196", utc);
136 final AbsoluteDate tC = new AbsoluteDate("1969-08-28T00:29:58.478894", utc);
137 final AbsoluteDate tD = new AbsoluteDate("1969-08-28T00:36:13.390275", utc);
138
139 List<LoggedEvent> events = logger.getLoggedEvents();
140 final AbsoluteDate t0 = events.get(0).getState().getDate();
141 final AbsoluteDate t1 = events.get(1).getState().getDate();
142 Assertions.assertEquals(2, events.size());
143 Assertions.assertEquals(0, t0.durationFrom(tB), 1.0e-6);
144 Assertions.assertEquals(0, t1.durationFrom(tC), 1.0e-6);
145
146 for (double dt = 0; dt < 3600; dt += 10.0) {
147 AbsoluteDate t = initialOrbit.getDate().shiftedBy(dt);
148 double[] angles = dihedralAngles(center, axis1, axis2,
149 sunPV.getPVCoordinates(t, initialOrbit.getFrame()),
150 new KeplerianPropagator(initialOrbit, earthCenterAttitudeLaw).propagate(t));
151 if (t.compareTo(tA) < 0) {
152
153 Assertions.assertTrue(angles[0] < -halfAperture);
154 Assertions.assertTrue(angles[1] < -halfAperture);
155 } else if (t.compareTo(tB) < 0) {
156
157 Assertions.assertTrue(angles[0] < -halfAperture);
158 Assertions.assertTrue(angles[1] > -halfAperture);
159 Assertions.assertTrue(angles[1] < +halfAperture);
160 } else if (t.compareTo(tC) < 0) {
161
162 Assertions.assertTrue(angles[0] > -halfAperture);
163 Assertions.assertTrue(angles[0] < +halfAperture);
164 Assertions.assertTrue(angles[1] > -halfAperture);
165 Assertions.assertTrue(angles[1] < +halfAperture);
166 } else if (t.compareTo(tD) < 0) {
167
168 Assertions.assertTrue(angles[0] < -halfAperture);
169 Assertions.assertTrue(angles[1] > -halfAperture);
170 Assertions.assertTrue(angles[1] < +halfAperture);
171 } else {
172
173 Assertions.assertTrue(angles[0] < -halfAperture);
174 Assertions.assertTrue(angles[1] > +halfAperture);
175 }
176 }
177
178 }
179
180 private double[] dihedralAngles(final Vector3D center, final Vector3D axis1, final Vector3D axis2,
181 final PVCoordinates target, final SpacecraftState s) {
182 final Rotation toInert = s.getAttitude().getOrientation().getRotation().revert();
183 final Vector3D centerInert = toInert.applyTo(center);
184 final Vector3D axis1Inert = toInert.applyTo(axis1);
185 final Vector3D axis2Inert = toInert.applyTo(axis2);
186 final Vector3D direction = target.getPosition().subtract(s.getPosition()).normalize();
187 return new double[] {
188 dihedralAngle(centerInert, axis1Inert, direction),
189 dihedralAngle(centerInert, axis2Inert, direction)
190 };
191 }
192
193 private double dihedralAngle(final Vector3D center, final Vector3D axis, final Vector3D u) {
194 final Vector3D y = Vector3D.crossProduct(axis, center).normalize();
195 final Vector3D x = Vector3D.crossProduct(y, axis).normalize();
196 return FastMath.atan2(Vector3D.dotProduct(u, y), Vector3D.dotProduct(u, x));
197 }
198
199
200 @Test
201 public void testStopOnExit() {
202
203 double pi = FastMath.PI;
204 AbsoluteDate date = AbsoluteDate.J2000_EPOCH;
205 AbsoluteDate endDate = date.shiftedBy(Constants.JULIAN_DAY);
206 Frame eci = FramesFactory.getGCRF();
207 Frame ecef = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
208 BodyShape earth = new OneAxisEllipsoid(
209 Constants.WGS84_EARTH_EQUATORIAL_RADIUS,
210 Constants.WGS84_EARTH_FLATTENING,
211 ecef);
212 GeodeticPoint gp = new GeodeticPoint(
213 FastMath.toRadians(39), FastMath.toRadians(77), 0);
214 TopocentricFrame topo = new TopocentricFrame(earth, gp, "topo");
215
216 KeplerianOrbit orbit = new KeplerianOrbit(
217 6378137 + 400e3, 0, FastMath.toRadians(51.65), 0, 0, 0,
218 PositionAngleType.TRUE, eci, date, Constants.EGM96_EARTH_MU);
219 AttitudeProvider attitude = new NadirPointing(eci, earth);
220
221
222 FieldOfView fov =
223 new PolygonalFieldOfView(Vector3D.PLUS_K,
224 DefiningConeType.INSIDE_CONE_TOUCHING_POLYGON_AT_EDGES_MIDDLE,
225 Vector3D.PLUS_I, pi / 3, 16, 0);
226 FieldOfViewDetector fovDetector =
227 new FieldOfViewDetector(topo, fov)
228 .withMaxCheck(5.0);
229 EventsLogger logger = new EventsLogger();
230
231 Propagator prop = new KeplerianPropagator(orbit, attitude);
232 prop.addEventDetector(logger.monitorDetector(fovDetector));
233 prop.propagate(endDate);
234 List<LoggedEvent> actual = logger.getLoggedEvents();
235
236
237
238 Assertions.assertEquals(2, actual.size());
239 }
240
241 @Test
242 public void testRadius() {
243
244
245
246
247
248 KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit, earthCenterAttitudeLaw);
249
250
251 final double halfAperture = FastMath.toRadians(0.5 * 68.0);
252 final double maxCheck = 60.;
253 final double threshold = 1.0e-10;
254 final PVCoordinatesProvider sun = CelestialBodyFactory.getSun();
255 final Vector3D center = Vector3D.PLUS_I;
256 final Vector3D axis1 = Vector3D.PLUS_K;
257 final Vector3D axis2 = Vector3D.PLUS_J;
258 final double aperture1 = halfAperture;
259 final double aperture2 = halfAperture;
260 final FieldOfView fov = new DoubleDihedraFieldOfView(center, axis1, aperture1, axis2, aperture2, 0.0);
261
262 final EventDetector sunCenter =
263 new FieldOfViewDetector(sun, fov).
264 withMaxCheck(maxCheck).
265 withThreshold(threshold).
266 withHandler(new ContinueOnEvent());
267
268 final EventDetector sunFull =
269 new FieldOfViewDetector(sun, Constants.SUN_RADIUS,
270 VisibilityTrigger.VISIBLE_ONLY_WHEN_FULLY_IN_FOV,
271 fov).
272 withMaxCheck(maxCheck).
273 withThreshold(threshold).
274 withHandler(new ContinueOnEvent());
275
276 final EventDetector sunPartial =
277 new FieldOfViewDetector(sun, Constants.SUN_RADIUS,
278 VisibilityTrigger.VISIBLE_AS_SOON_AS_PARTIALLY_IN_FOV,
279 fov).
280 withMaxCheck(maxCheck).
281 withThreshold(threshold).
282 withHandler(new ContinueOnEvent());
283
284 Assertions.assertSame(sun, ((FieldOfViewDetector) sunCenter).getPVTarget());
285 Assertions.assertEquals(0, ((FieldOfViewDetector) sunCenter).getFOV().getMargin(), 1.0e-15);
286 double eta = FastMath.acos(FastMath.sin(aperture1) * FastMath.sin(aperture2));
287 double theoreticalArea = MathUtils.TWO_PI - 4 * eta;
288 Assertions.assertEquals(theoreticalArea,
289 ((PolygonalFieldOfView) ((FieldOfViewDetector) sunCenter).getFOV()).getZone().getSize(),
290 1.0e-15);
291
292
293 EventsLogger logger = new EventsLogger();
294 propagator.addEventDetector(logger.monitorDetector(sunCenter));
295 propagator.addEventDetector(logger.monitorDetector(sunFull));
296 propagator.addEventDetector(logger.monitorDetector(sunPartial));
297
298
299 propagator.propagate(initDate.shiftedBy(6000.));
300
301 List<LoggedEvent> events = logger.getLoggedEvents();
302 Assertions.assertEquals(6, events.size());
303 Assertions.assertSame(sunPartial, events.get(0).getEventDetector());
304 Assertions.assertEquals(460.876793, events.get(0).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
305 Assertions.assertSame(sunCenter, events.get(1).getEventDetector());
306 Assertions.assertEquals(488.299210, events.get(1).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
307 Assertions.assertSame(sunFull, events.get(2).getEventDetector());
308 Assertions.assertEquals(517.536353, events.get(2).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
309 Assertions.assertSame(sunFull, events.get(3).getEventDetector());
310 Assertions.assertEquals(1749.277930, events.get(3).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
311 Assertions.assertSame(sunCenter, events.get(4).getEventDetector());
312 Assertions.assertEquals(1798.478948, events.get(4).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
313 Assertions.assertSame(sunPartial, events.get(5).getEventDetector());
314 Assertions.assertEquals(1845.979622, events.get(5).getState().getDate().durationFrom(initialOrbit.getDate()), 1.0e-6);
315
316 }
317
318 @Test
319 public void testMatryoshka() {
320
321
322
323
324
325 KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit, earthCenterAttitudeLaw);
326
327 final PVCoordinatesProvider sun = CelestialBodyFactory.getSun();
328 final double maxCheck = 60.;
329 final double threshold = 1.0e-10;
330 EventsLogger logger = new EventsLogger();
331
332
333 CircularFieldOfView circFov = new CircularFieldOfView(Vector3D.PLUS_I, FastMath.toRadians(0.5 * 68.0), 0.0);
334 List<EventDetector> detectors = new ArrayList<>();
335 for (int i = 0; i < 4; ++i) {
336
337
338 final EventDetector circDetector =
339 new FieldOfViewDetector(sun, circFov).
340 withMaxCheck(maxCheck).
341 withThreshold(threshold).
342 withHandler(new ContinueOnEvent());
343 detectors.add(circDetector);
344 propagator.addEventDetector(logger.monitorDetector(circDetector));
345
346
347 PolygonalFieldOfView polyFov = new PolygonalFieldOfView(circFov.getCenter(),
348 DefiningConeType.OUTSIDE_CONE_TOUCHING_POLYGON_AT_VERTICES,
349 circFov.getCenter().orthogonal(),
350 circFov.getHalfAperture(), 16, 0.0);
351 final EventDetector polyDetector =
352 new FieldOfViewDetector(sun, polyFov).
353 withMaxCheck(maxCheck).
354 withThreshold(threshold).
355 withHandler(new ContinueOnEvent());
356 detectors.add(polyDetector);
357 propagator.addEventDetector(logger.monitorDetector(polyDetector));
358
359
360 final Edge edge = polyFov.getZone().getBoundaryLoops().get(0).getOutgoing();
361 final Vector3D middle = edge.getPointAt(0.5 * edge.getLength());
362 final double innerRadius = Vector3D.angle(circFov.getCenter(), middle);
363 circFov = new CircularFieldOfView(circFov.getCenter(), innerRadius, 0.0);
364
365 }
366
367
368 propagator.propagate(initDate.shiftedBy(6000.));
369
370 int n = detectors.size();
371 List<LoggedEvent> events = logger.getLoggedEvents();
372 Assertions.assertEquals(2 * n, events.size());
373
374
375 for (int i = 0; i < n; ++i) {
376 Assertions.assertSame(detectors.get(i), events.get(i).getEventDetector());
377 }
378
379
380 for (int i = 0; i < n; ++i) {
381 Assertions.assertSame(detectors.get(n - 1 - i), events.get(n + i).getEventDetector());
382 }
383
384 }
385
386 @Test
387 public void testElliptical() {
388
389
390
391
392
393 KeplerianPropagator propagator = new KeplerianPropagator(initialOrbit, earthCenterAttitudeLaw);
394
395 final PVCoordinatesProvider sun = CelestialBodyFactory.getSun();
396 final double maxCheck = 60.;
397 final double threshold = 1.0e-10;
398 EventsLogger logger = new EventsLogger();
399
400 EllipticalFieldOfView fov = new EllipticalFieldOfView(Vector3D.PLUS_I, Vector3D.PLUS_J,
401 FastMath.toRadians(40), FastMath.toRadians(10),
402 0.0);
403 propagator.addEventDetector(logger.monitorDetector(new FieldOfViewDetector(sun, fov).
404 withMaxCheck(maxCheck).
405 withThreshold(threshold).
406 withHandler(new ContinueOnEvent())));
407
408
409 propagator.propagate(initDate.shiftedBy(6000.));
410
411 List<LoggedEvent> events = logger.getLoggedEvents();
412 Assertions.assertEquals(2, events.size());
413
414 Assertions.assertFalse(events.get(0).isIncreasing());
415 Assertions.assertEquals(881.897, events.get(0).getState().getDate().durationFrom(initDate), 1.0e-3);
416 Assertions.assertTrue(events.get(1).isIncreasing());
417 Assertions.assertEquals(1242.146, events.get(1).getState().getDate().durationFrom(initDate), 1.0e-3);
418
419 }
420
421 @BeforeEach
422 public void setUp() {
423 try {
424
425 Utils.setDataRoot("regular-data");
426
427 utc = TimeScalesFactory.getUTC();
428
429
430
431 mu = 3.9860047e14;
432
433 initDate = new AbsoluteDate(new DateComponents(1969, 8, 28), TimeComponents.H00, utc);
434
435 Vector3D position = new Vector3D(7.0e6, 1.0e6, 4.0e6);
436 Vector3D velocity = new Vector3D(-500.0, 8000.0, 1000.0);
437 initialOrbit = new EquinoctialOrbit(new PVCoordinates(position, velocity),
438 FramesFactory.getEME2000(), initDate, mu);
439
440
441
442 earth = new OneAxisEllipsoid(Constants.WGS84_EARTH_EQUATORIAL_RADIUS,
443 Constants.WGS84_EARTH_FLATTENING,
444 FramesFactory.getITRF(IERSConventions.IERS_2010, true));
445
446
447 earthCenterAttitudeLaw = new BodyCenterPointing(initialOrbit.getFrame(), earth);
448
449 } catch (OrekitException oe) {
450 Assertions.fail(oe.getMessage());
451 }
452
453 }
454
455
456
457 private static class DihedralSunVisiHandler implements EventHandler {
458
459 public Action eventOccurred(final SpacecraftState s, final EventDetector detector,
460 final boolean increasing) {
461 if (increasing) {
462
463 AbsoluteDate startVisiDate = new AbsoluteDate(new DateComponents(1969, 8, 28),
464 new TimeComponents(1, 19, 00.381),
465 TimeScalesFactory.getUTC());
466
467 Assertions.assertTrue(s.getDate().durationFrom(startVisiDate) <= 1);
468 return Action.CONTINUE;
469 } else {
470 AbsoluteDate endVisiDate = new AbsoluteDate(new DateComponents(1969, 8, 28),
471 new TimeComponents(1, 39 , 42.674),
472 TimeScalesFactory.getUTC());
473 Assertions.assertTrue(s.getDate().durationFrom(endVisiDate) <= 1);
474
475 return Action.CONTINUE;
476 }
477 }
478
479 }
480
481 }