1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17 package org.orekit.estimation.measurements.generation;
18
19 import java.util.Map;
20 import java.util.SortedSet;
21
22 import org.hipparchus.linear.MatrixUtils;
23 import org.hipparchus.linear.RealMatrix;
24 import org.hipparchus.random.CorrelatedRandomVectorGenerator;
25 import org.hipparchus.random.GaussianRandomGenerator;
26 import org.hipparchus.random.RandomGenerator;
27 import org.hipparchus.random.Well19937a;
28 import org.hipparchus.util.FastMath;
29 import org.junit.Assert;
30 import org.junit.Before;
31 import org.junit.Test;
32 import org.orekit.estimation.Context;
33 import org.orekit.estimation.EstimationTestUtils;
34 import org.orekit.estimation.Force;
35 import org.orekit.estimation.measurements.GroundStation;
36 import org.orekit.estimation.measurements.ObservableSatellite;
37 import org.orekit.estimation.measurements.ObservedMeasurement;
38 import org.orekit.estimation.measurements.TurnAroundRange;
39 import org.orekit.estimation.measurements.modifiers.Bias;
40 import org.orekit.orbits.OrbitType;
41 import org.orekit.orbits.PositionAngle;
42 import org.orekit.propagation.Propagator;
43 import org.orekit.propagation.SpacecraftState;
44 import org.orekit.propagation.conversion.NumericalPropagatorBuilder;
45 import org.orekit.propagation.events.BooleanDetector;
46 import org.orekit.propagation.events.ElevationDetector;
47 import org.orekit.time.AbsoluteDate;
48 import org.orekit.time.FixedStepSelector;
49 import org.orekit.time.TimeScalesFactory;
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(new ElevationDetector(primary.getBaseFrame()).
102 withConstantElevation(FastMath.toRadians(5.0)),
103 new ElevationDetector(secondary.getBaseFrame()).
104 withConstantElevation(FastMath.toRadians(5.0))),
105 SignSemantic.FEASIBLE_MEASUREMENT_WHEN_POSITIVE));
106 final double period = context.initialOrbit.getKeplerianPeriod();
107 AbsoluteDate t0 = context.initialOrbit.getDate().shiftedBy(startPeriod * period);
108 AbsoluteDate t1 = context.initialOrbit.getDate().shiftedBy(endPeriod * period);
109 SortedSet<ObservedMeasurement<?>> measurements = generator.generate(t0, t1);
110 Propagator propagator = buildPropagator();
111 double maxError = 0;
112 AbsoluteDate previous = null;
113 AbsoluteDate tInf = t0.compareTo(t1) < 0 ? t0 : t1;
114 AbsoluteDate tSup = t0.compareTo(t1) < 0 ? t1 : t0;
115 for (ObservedMeasurement<?> measurement : measurements) {
116 AbsoluteDate date = measurement.getDate();
117 double[] m = measurement.getObservedValue();
118 Assert.assertTrue(date.compareTo(tInf) >= 0);
119 Assert.assertTrue(date.compareTo(tSup) <= 0);
120 if (previous != null) {
121
122
123
124 Assert.assertTrue(date.durationFrom(previous) >= 0.999999 * step);
125 }
126 previous = date;
127 SpacecraftState state = propagator.propagate(date);
128 double[] e = measurement.estimate(0, 0, new SpacecraftState[] { state }).getEstimatedValue();
129 for (int i = 0; i < m.length; ++i) {
130 maxError = FastMath.max(maxError, FastMath.abs(e[i] - m[i]));
131 }
132 }
133 Assert.assertEquals(0.0, maxError, tolerance);
134 }
135
136 @Before
137 public void setUp() {
138 context = EstimationTestUtils.eccentricContext("regular-data:potential:tides");
139
140 propagatorBuilder = context.createBuilder(OrbitType.KEPLERIAN, PositionAngle.TRUE, true,
141 1.0e-6, 300.0, 0.001, Force.POTENTIAL,
142 Force.THIRD_BODY_SUN, Force.THIRD_BODY_MOON);
143 }
144
145 Context context;
146 NumericalPropagatorBuilder propagatorBuilder;
147
148 }