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17 package org.orekit.estimation.measurements.generation;
18
19 import java.util.SortedSet;
20
21 import org.hipparchus.linear.MatrixUtils;
22 import org.hipparchus.linear.RealMatrix;
23 import org.hipparchus.random.CorrelatedRandomVectorGenerator;
24 import org.hipparchus.random.GaussianRandomGenerator;
25 import org.hipparchus.random.RandomGenerator;
26 import org.hipparchus.random.Well19937a;
27 import org.hipparchus.util.FastMath;
28 import org.junit.jupiter.api.Assertions;
29 import org.junit.jupiter.api.BeforeEach;
30 import org.junit.jupiter.api.Test;
31 import org.orekit.estimation.Context;
32 import org.orekit.estimation.EstimationTestUtils;
33 import org.orekit.estimation.Force;
34 import org.orekit.estimation.measurements.EstimatedMeasurementBase;
35 import org.orekit.estimation.measurements.ObservableSatellite;
36 import org.orekit.estimation.measurements.gnss.AmbiguityCache;
37 import org.orekit.estimation.measurements.gnss.OneWayGNSSPhase;
38 import org.orekit.estimation.measurements.modifiers.Bias;
39 import org.orekit.gnss.PredefinedGnssSignal;
40 import org.orekit.orbits.KeplerianOrbit;
41 import org.orekit.orbits.Orbit;
42 import org.orekit.orbits.OrbitType;
43 import org.orekit.orbits.PositionAngleType;
44 import org.orekit.propagation.Propagator;
45 import org.orekit.propagation.SpacecraftState;
46 import org.orekit.propagation.analytical.KeplerianPropagator;
47 import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
48 import org.orekit.propagation.events.InterSatDirectViewDetector;
49 import org.orekit.time.AbsoluteDate;
50 import org.orekit.time.FixedStepSelector;
51 import org.orekit.time.TimeScalesFactory;
52 import org.orekit.utils.PVCoordinates;
53
54 public class OneWayGNSSPhaseBuilderTest {
55
56 private static final double SIGMA = 0.5;
57 private static final double BIAS = -0.01;
58 private static final double WAVELENGTH = PredefinedGnssSignal.G01.getWavelength();
59
60 private MeasurementBuilder<OneWayGNSSPhase> getBuilder(final RandomGenerator random,
61 final ObservableSatellite receiver,
62 final ObservableSatellite remote) {
63 final RealMatrix covariance = MatrixUtils.createRealDiagonalMatrix(new double[] { SIGMA * SIGMA });
64 remote.getClockOffsetDriver().setValue(1.0e-16);
65 remote.getClockDriftDriver().setValue(0);
66 remote.getClockAccelerationDriver().setValue(0);
67 MeasurementBuilder<OneWayGNSSPhase> b =
68 new OneWayGNSSPhaseBuilder(random == null ? null : new CorrelatedRandomVectorGenerator(covariance,
69 1.0e-10,
70 new GaussianRandomGenerator(random)),
71 receiver, remote,
72 WAVELENGTH, SIGMA, 1.0,
73 new AmbiguityCache());
74 b.addModifier(new Bias<>(new String[] { "bias" },
75 new double[] { BIAS },
76 new double[] { 1.0 },
77 new double[] { Double.NEGATIVE_INFINITY },
78 new double[] { Double.POSITIVE_INFINITY }));
79 return b;
80 }
81
82 @Test
83 public void testForward() {
84 doTest(0x812bfe784826bab3L, 0.0, 1.2, 3.4 * SIGMA);
85 }
86
87 @Test
88 public void testBackward() {
89 doTest(0xb54896c361d88441L, 0.0, -1.0, 2.8 * SIGMA);
90 }
91
92 private Propagator buildPropagator() {
93 return EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
94 }
95
96 private void doTest(long seed, double startPeriod, double endPeriod, double tolerance) {
97 Generator generator = new Generator();
98 generator.addPropagator(buildPropagator());
99 generator.addPropagator(buildPropagator());
100 ObservableSatellite receiver = generator.addPropagator(buildPropagator());
101 generator.addPropagator(buildPropagator());
102 final Orbit o1 = context.initialOrbit;
103
104 final Orbit o2 = new KeplerianOrbit(new PVCoordinates(o1.getPosition(),
105 o1.getPVCoordinates().getVelocity().negate()),
106 o1.getFrame(), o1.getDate(), o1.getMu());
107 ObservableSatellite remote = generator.addPropagator(new KeplerianPropagator(o2));
108 final double step = 60.0;
109
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112
113
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115 generator.addScheduler(new EventBasedScheduler<>(getBuilder(new Well19937a(seed), receiver, remote),
116 new FixedStepSelector(step, TimeScalesFactory.getUTC()),
117 generator.getPropagator(receiver),
118 new InterSatDirectViewDetector(context.earth, new KeplerianPropagator(o2)),
119 SignSemantic.FEASIBLE_MEASUREMENT_WHEN_POSITIVE));
120
121 final GatheringSubscriber gatherer = new GatheringSubscriber();
122 generator.addSubscriber(gatherer);
123 final double period = o1.getKeplerianPeriod();
124 AbsoluteDate t0 = o1.getDate().shiftedBy(startPeriod * period);
125 AbsoluteDate t1 = o1.getDate().shiftedBy(endPeriod * period);
126 generator.generate(t0, t1);
127 SortedSet<EstimatedMeasurementBase<?>> measurements = gatherer.getGeneratedMeasurements();
128
129
130 Propagator propagator1 = buildPropagator();
131 Propagator propagator2 = new KeplerianPropagator(o2);
132
133 double maxError = 0;
134 AbsoluteDate previous = null;
135 AbsoluteDate tInf = t0.isBefore(t1) ? t0 : t1;
136 AbsoluteDate tSup = t0.isBefore(t1) ? t1 : t0;
137 for (EstimatedMeasurementBase<?> measurement : measurements) {
138 AbsoluteDate date = measurement.getDate();
139 double[] m = measurement.getObservedValue();
140 Assertions.assertTrue(date.compareTo(tInf) >= 0);
141 Assertions.assertTrue(date.compareTo(tSup) <= 0);
142 if (previous != null) {
143 if (t0.isBefore(t1)) {
144
145 Assertions.assertTrue(date.durationFrom(previous) >= 0.999999 * step);
146 } else {
147
148 Assertions.assertTrue(previous.durationFrom(date) >= 0.999999 * step);
149 }
150 }
151 previous = date;
152 double[] e = measurement.
153 getObservedMeasurement().
154 estimateWithoutDerivatives(new SpacecraftState[] {
155 propagator1.propagate(date),
156 propagator2.propagate(date)
157 }).
158 getEstimatedValue();
159 for (int i = 0; i < m.length; ++i) {
160 maxError = FastMath.max(maxError, FastMath.abs(e[i] - m[i]));
161 }
162 }
163 Assertions.assertEquals(0.0, maxError, tolerance);
164 }
165
166 @BeforeEach
167 public void setUp() {
168 context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
169
170 propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngleType.TRUE, true,
171 1.0e-6, 300.0, 0.001, Force.POTENTIAL,
172 Force.THIRD_BODY_SUN, Force.THIRD_BODY_MOON);
173 }
174
175 Context context;
176 NumericalPropagatorBuilder propagatorBuilder;
177
178 }