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17  package org.orekit.estimation.measurements.modifiers;
18  
19  import java.util.List;
20  
21  import org.hipparchus.geometry.euclidean.threed.Vector3D;
22  import org.junit.jupiter.api.Assertions;
23  import org.junit.jupiter.api.Test;
24  import org.orekit.attitudes.LofOffset;
25  import org.orekit.estimation.Context;
26  import org.orekit.estimation.EstimationTestUtils;
27  import org.orekit.estimation.measurements.EstimatedMeasurementBase;
28  import org.orekit.estimation.measurements.InterSatellitesRange;
29  import org.orekit.estimation.measurements.InterSatellitesRangeMeasurementCreator;
30  import org.orekit.estimation.measurements.ObservedMeasurement;
31  import org.orekit.frames.LOFType;
32  import org.orekit.orbits.CartesianOrbit;
33  import org.orekit.orbits.Orbit;
34  import org.orekit.orbits.OrbitType;
35  import org.orekit.orbits.PositionAngleType;
36  import org.orekit.propagation.BoundedPropagator;
37  import org.orekit.propagation.EphemerisGenerator;
38  import org.orekit.propagation.Propagator;
39  import org.orekit.propagation.SpacecraftState;
40  import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
41  import org.orekit.utils.TimeStampedPVCoordinates;
42  
43  public class OnBoardAntennaInterSatellitesRangeModifierTest {
44  
45      @Test
46      public void testPreliminary() {
47  
48          // this test does not check OnBoardAntennaInterSatellitesRangeModifier at all,
49          // it just checks InterSatellitesRangeMeasurementCreator behaves as necessary for the other test
50          // the *real* test is testEffect below
51          Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
52  
53          final NumericalPropagatorBuilder propagatorBuilder =
54                          context.createBuilder(OrbitType.KEPLERIAN, PositionAngleType.TRUE, true,
55                                                1.0e-6, 60.0, 0.001);
56          propagatorBuilder.setAttitudeProvider(new LofOffset(propagatorBuilder.getFrame(), LOFType.LVLH));
57  
58          // create perfect inter-satellites range measurements without antenna offset
59          final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
60          final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(),
61                                                                                   original.getPosition().add(new Vector3D(1000, 2000, 3000)),
62                                                                                   original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))),
63                                                      context.initialOrbit.getFrame(),
64                                                      context.initialOrbit.getMu());
65          final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit,
66                                                                                  propagatorBuilder);
67          final EphemerisGenerator generator = closePropagator.getEphemerisGenerator();
68          closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
69          final BoundedPropagator ephemeris = generator.getGeneratedEphemeris();
70          final Propagator p1 = EstimationTestUtils.createPropagator(context.initialOrbit,
71                                                                             propagatorBuilder);
72          final double localClockOffset  = 0.137e-6;
73          final double remoteClockOffset = 469.0e-6;
74          final List<ObservedMeasurement<?>> spacecraftCenteredMeasurements =
75                          EstimationTestUtils.createMeasurements(p1,
76                                                                 new InterSatellitesRangeMeasurementCreator(ephemeris,
77                                                                                                            localClockOffset,
78                                                                                                            remoteClockOffset,
79                                                                                                            Vector3D.ZERO,
80                                                                                                            Vector3D.ZERO),
81                                                                 1.0, 3.0, 300.0);
82  
83          // create perfect inter-satellites range measurements with antenna offset
84          final double xOffset1 = -2.5;
85          final double yOffset2 =  0.8;
86          final Propagator p2 = EstimationTestUtils.createPropagator(context.initialOrbit,
87                                                                     propagatorBuilder);
88          final List<ObservedMeasurement<?>> antennaCenteredMeasurements =
89                          EstimationTestUtils.createMeasurements(p2,
90                                                                 new InterSatellitesRangeMeasurementCreator(ephemeris,
91                                                                                                            localClockOffset,
92                                                                                                            remoteClockOffset,
93                                                                                                            new Vector3D(xOffset1, 0, 0),
94                                                                                                            new Vector3D(0, yOffset2, 0)),
95                                                                 1.0, 3.0, 300.0);
96  
97          for (int i = 0; i < spacecraftCenteredMeasurements.size(); ++i) {
98              InterSatellitesRange sr = (InterSatellitesRange) spacecraftCenteredMeasurements.get(i);
99              InterSatellitesRange ar = (InterSatellitesRange) antennaCenteredMeasurements.get(i);
100             Assertions.assertEquals(0.0, sr.getDate().durationFrom(ar.getDate()), 2.0e-8);
101             Assertions.assertTrue(ar.getObservedValue()[0] - sr.getObservedValue()[0] >= -1.0);
102             Assertions.assertTrue(ar.getObservedValue()[0] - sr.getObservedValue()[0] <= -0.36);
103         }
104     }
105 
106     @Test
107     public void testEffect() {
108 
109         Context context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
110 
111         final NumericalPropagatorBuilder propagatorBuilder =
112                         context.createBuilder(OrbitType.KEPLERIAN, PositionAngleType.TRUE, true,
113                                               1.0e-6, 60.0, 0.001);
114         propagatorBuilder.setAttitudeProvider(new LofOffset(propagatorBuilder.getFrame(), LOFType.LVLH));
115 
116         // create perfect inter-satellites range measurements without antenna offset
117         final TimeStampedPVCoordinates original = context.initialOrbit.getPVCoordinates();
118         final Orbit closeOrbit = new CartesianOrbit(new TimeStampedPVCoordinates(context.initialOrbit.getDate(),
119                                                                                  original.getPosition().add(new Vector3D(1000, 2000, 3000)),
120                                                                                  original.getVelocity().add(new Vector3D(-0.03, 0.01, 0.02))),
121                                                     context.initialOrbit.getFrame(),
122                                                     context.initialOrbit.getMu());
123         final Propagator closePropagator = EstimationTestUtils.createPropagator(closeOrbit,
124                                                                                 propagatorBuilder);
125         final EphemerisGenerator generator = closePropagator.getEphemerisGenerator();
126         closePropagator.propagate(context.initialOrbit.getDate().shiftedBy(3.5 * closeOrbit.getKeplerianPeriod()));
127         final BoundedPropagator ephemeris = generator.getGeneratedEphemeris();
128         final Propagator p1 = EstimationTestUtils.createPropagator(context.initialOrbit,
129                                                                            propagatorBuilder);
130         final double localClockOffset  = 0.137e-6;
131         final double remoteClockOffset = 469.0e-6;
132         final List<ObservedMeasurement<?>> spacecraftCenteredMeasurements =
133                         EstimationTestUtils.createMeasurements(p1,
134                                                                new InterSatellitesRangeMeasurementCreator(ephemeris,
135                                                                                                           localClockOffset,
136                                                                                                           remoteClockOffset,
137                                                                                                           Vector3D.ZERO,
138                                                                                                           Vector3D.ZERO),
139                                                                1.0, 3.0, 300.0);
140 
141         // create perfect inter-satellites range measurements with antenna offset
142         final Vector3D apc1 = new Vector3D(-2.5, 0.0, 0);
143         final Vector3D apc2 = new Vector3D( 0.0, 0.8, 0);
144         final Propagator p2 = EstimationTestUtils.createPropagator(context.initialOrbit,
145                                                                    propagatorBuilder);
146         final List<ObservedMeasurement<?>> antennaCenteredMeasurements =
147                         EstimationTestUtils.createMeasurements(p2,
148                                                                new InterSatellitesRangeMeasurementCreator(ephemeris,
149                                                                                                           localClockOffset,
150                                                                                                           remoteClockOffset,
151                                                                                                           apc1, apc2),
152                                                                1.0, 3.0, 300.0);
153 
154         final Propagator p3 = EstimationTestUtils.createPropagator(context.initialOrbit,
155                                                                    propagatorBuilder);
156 
157         OnBoardAntennaInterSatellitesRangeModifier modifier = new OnBoardAntennaInterSatellitesRangeModifier(apc1, apc2);
158         for (int i = 0; i < spacecraftCenteredMeasurements.size(); ++i) {
159             InterSatellitesRange sr = (InterSatellitesRange) spacecraftCenteredMeasurements.get(i);
160             sr.addModifier(modifier);
161             EstimatedMeasurementBase<InterSatellitesRange> estimated = sr.estimateWithoutDerivatives(new SpacecraftState[] {
162                                                                                                          p3.propagate(sr.getDate()),
163                                                                                                          ephemeris.propagate(sr.getDate())
164                                                                                                      });
165             InterSatellitesRange ar = (InterSatellitesRange) antennaCenteredMeasurements.get(i);
166             Assertions.assertEquals(0.0, sr.getDate().durationFrom(ar.getDate()), 2.0e-8);
167             Assertions.assertEquals(ar.getObservedValue()[0], estimated.getEstimatedValue()[0], 2.0e-5);
168             Assertions.assertEquals(1,
169                                     estimated.getAppliedEffects().entrySet().stream().
170                                     filter(e -> e.getKey().getEffectName().equals("mean phase center")).count());
171         }
172 
173     }
174 
175 }
176 
177