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17 package org.orekit.estimation.measurements.generation;
18
19 import org.hipparchus.linear.MatrixUtils;
20 import org.hipparchus.linear.RealMatrix;
21 import org.hipparchus.random.CorrelatedRandomVectorGenerator;
22 import org.hipparchus.random.GaussianRandomGenerator;
23 import org.hipparchus.random.RandomGenerator;
24 import org.hipparchus.random.Well19937a;
25 import org.hipparchus.util.FastMath;
26 import org.junit.jupiter.api.Assertions;
27 import org.junit.jupiter.api.BeforeEach;
28 import org.junit.jupiter.api.Test;
29 import org.orekit.estimation.Context;
30 import org.orekit.estimation.EstimationTestUtils;
31 import org.orekit.estimation.Force;
32 import org.orekit.estimation.measurements.EstimatedMeasurementBase;
33 import org.orekit.estimation.measurements.GroundStation;
34 import org.orekit.estimation.measurements.ObservableSatellite;
35 import org.orekit.estimation.measurements.TurnAroundRange;
36 import org.orekit.estimation.measurements.modifiers.Bias;
37 import org.orekit.orbits.OrbitType;
38 import org.orekit.orbits.PositionAngleType;
39 import org.orekit.propagation.Propagator;
40 import org.orekit.propagation.SpacecraftState;
41 import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
42 import org.orekit.propagation.events.BooleanDetector;
43 import org.orekit.propagation.events.ElevationDetector;
44 import org.orekit.time.AbsoluteDate;
45 import org.orekit.time.FixedStepSelector;
46 import org.orekit.time.TimeScalesFactory;
47
48 import java.util.Map;
49 import java.util.SortedSet;
50
51 public class TurnAroundRangeBuilderTest {
52
53 private static final double SIGMA = 10.0;
54 private static final double BIAS = -7.0;
55
56 private MeasurementBuilder<TurnAroundRange> getBuilder(final RandomGenerator random,
57 final GroundStation primary,
58 final GroundStation secondary,
59 final ObservableSatellite satellite) {
60 final RealMatrix covariance = MatrixUtils.createRealDiagonalMatrix(new double[] { SIGMA * SIGMA });
61 MeasurementBuilder<TurnAroundRange> rb =
62 new TurnAroundRangeBuilder(random == null ? null : new CorrelatedRandomVectorGenerator(covariance,
63 1.0e-10,
64 new GaussianRandomGenerator(random)),
65 primary, secondary, SIGMA, 1.0, satellite);
66 rb.addModifier(new Bias<>(new String[] { "bias" },
67 new double[] { BIAS },
68 new double[] { 1.0 },
69 new double[] { Double.NEGATIVE_INFINITY },
70 new double[] { Double.POSITIVE_INFINITY }));
71 return rb;
72 }
73
74 @Test
75 public void testForward() {
76 doTest(0xf50c0ce7c8c1dab2L, 0.0, 1.2, 3.2 * SIGMA);
77 }
78
79 @Test
80 public void testBackward() {
81 doTest(0x453a681440d01832L, 0.0, -1.0, 2.6 * SIGMA);
82 }
83
84 private Propagator buildPropagator() {
85 return EstimationTestUtils.createPropagator(context.initialOrbit, propagatorBuilder);
86 }
87
88 private void doTest(long seed, double startPeriod, double endPeriod, double tolerance) {
89 Generator generator = new Generator();
90 final double step = 60.0;
91 final Map.Entry<GroundStation, GroundStation> entry = context.TARstations.entrySet().iterator().next();
92 final GroundStation primary = entry.getKey();
93 final GroundStation secondary = entry.getValue();
94 generator.addPropagator(buildPropagator());
95 generator.addPropagator(buildPropagator());
96 ObservableSatellite satellite = generator.addPropagator(buildPropagator());
97 generator.addPropagator(buildPropagator());
98 generator.addScheduler(new EventBasedScheduler<>(getBuilder(new Well19937a(seed), primary, secondary, satellite),
99 new FixedStepSelector(step, TimeScalesFactory.getUTC()),
100 generator.getPropagator(satellite),
101 BooleanDetector.andCombine(EstimationTestUtils.getElevationDetector(primary.getBaseFrame(),
102 FastMath.toRadians(5.0)),
103 EstimationTestUtils.getElevationDetector(secondary.getBaseFrame(),
104 FastMath.toRadians(5.0))),
105 SignSemantic.FEASIBLE_MEASUREMENT_WHEN_POSITIVE));
106 final GatheringSubscriber gatherer = new GatheringSubscriber();
107 generator.addSubscriber(gatherer);
108 final double period = context.initialOrbit.getKeplerianPeriod();
109 AbsoluteDate t0 = context.initialOrbit.getDate().shiftedBy(startPeriod * period);
110 AbsoluteDate t1 = context.initialOrbit.getDate().shiftedBy(endPeriod * period);
111 generator.generate(t0, t1);
112 SortedSet<EstimatedMeasurementBase<?>> measurements = gatherer.getGeneratedMeasurements();
113 Propagator propagator = buildPropagator();
114 double maxError = 0;
115 AbsoluteDate previous = null;
116 AbsoluteDate tInf = t0.isBefore(t1) ? t0 : t1;
117 AbsoluteDate tSup = t0.isBefore(t1) ? t1 : t0;
118 for (EstimatedMeasurementBase<?> measurement : measurements) {
119 AbsoluteDate date = measurement.getDate();
120 double[] m = measurement.getObservedValue();
121 Assertions.assertTrue(date.compareTo(tInf) >= 0);
122 Assertions.assertTrue(date.compareTo(tSup) <= 0);
123 if (previous != null) {
124 if (t0.isBefore(t1)) {
125
126 Assertions.assertTrue(date.durationFrom(previous) >= 0.999999 * step);
127 } else {
128
129 Assertions.assertTrue(previous.durationFrom(date) >= 0.999999 * step);
130 }
131 }
132 previous = date;
133 SpacecraftState state = propagator.propagate(date);
134 double[] e = measurement.
135 getObservedMeasurement().
136 estimateWithoutDerivatives(new SpacecraftState[] { state }).
137 getEstimatedValue();
138 for (int i = 0; i < m.length; ++i) {
139 maxError = FastMath.max(maxError, FastMath.abs(e[i] - m[i]));
140 }
141 }
142 Assertions.assertEquals(0.0, maxError, tolerance);
143 }
144
145 @BeforeEach
146 public void setUp() {
147 context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
148
149 propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngleType.TRUE, true,
150 1.0e-6, 300.0, 0.001, Force.POTENTIAL,
151 Force.THIRD_BODY_SUN, Force.THIRD_BODY_MOON);
152 }
153
154 Context context;
155 NumericalPropagatorBuilder propagatorBuilder;
156
157 }