1   /* Copyright 2002-2025 CS GROUP
2    * Licensed to CS GROUP (CS) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * CS licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *   http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.orekit.estimation.measurements.modifiers;
18  
19  import org.hipparchus.geometry.euclidean.threed.Vector3D;
20  import org.junit.jupiter.api.Assertions;
21  import org.junit.jupiter.api.BeforeEach;
22  import org.junit.jupiter.api.Test;
23  import org.orekit.Utils;
24  import org.orekit.estimation.measurements.EstimatedMeasurement;
25  import org.orekit.estimation.measurements.EstimatedMeasurementBase;
26  import org.orekit.estimation.measurements.EstimationModifier;
27  import org.orekit.estimation.measurements.InterSatellitesRange;
28  import org.orekit.estimation.measurements.ObservableSatellite;
29  import org.orekit.propagation.SpacecraftState;
30  import org.orekit.propagation.analytical.tle.TLE;
31  import org.orekit.propagation.analytical.tle.TLEPropagator;
32  import org.orekit.time.AbsoluteDate;
33  import org.orekit.time.TimeScalesFactory;
34  
35  public class RelativisticClockInterSatellitesRangeModifierTest {
36  
37      /** Date. */
38      private static AbsoluteDate date;
39  
40      /** Spacecraft states. */
41      private static SpacecraftState[] states;
42  
43      @Test
44      public void testRelativisticClockCorrection() {
45  
46          // Measurement
47          final InterSatellitesRange range = new InterSatellitesRange(new ObservableSatellite(0), new ObservableSatellite(1),
48                                                                      false, date,
49                                                                      Vector3D.distance(states[0].getPosition(),
50                                                                                        states[1].getPosition()),
51                                                                      1.0, 1.0);
52  
53          // Inter-satellites range before applying the modifier
54          final EstimatedMeasurementBase<InterSatellitesRange> estimatedBefore = range.estimateWithoutDerivatives(states);
55  
56          // Inter-satellites range before applying the modifier
57          final EstimationModifier<InterSatellitesRange> modifier = new RelativisticClockInterSatellitesRangeModifier();
58          range.addModifier(modifier);
59          final EstimatedMeasurement<InterSatellitesRange> estimatedAfter = range.estimate(0, 0, states);
60  
61          // Verify
62          Assertions.assertEquals(-10.57, estimatedBefore.getEstimatedValue()[0] - estimatedAfter.getEstimatedValue()[0], 1.0e-2);
63          Assertions.assertEquals(0, modifier.getParametersDrivers().size());
64          Assertions.assertEquals(1,
65                                  estimatedAfter.getAppliedEffects().entrySet().stream().
66                                  filter(e -> e.getKey().getEffectName().equals("clock relativity")).count());
67  
68      }
69  
70      @BeforeEach
71      public void setUp() {
72          // Data root
73          Utils.setDataRoot("regular-data");
74  
75          // Date
76          date = new AbsoluteDate("2004-01-13T00:00:00.000", TimeScalesFactory.getUTC());
77  
78          // Spacecraft states
79          states = new SpacecraftState[2];
80          final TLE local = new TLE("1 27642U 03002A   04013.91734903  .00000108  00000-0  12227-4 0  3621",
81                                    "2 27642  93.9970   6.8623 0003169  80.1383 280.0205 14.90871424 54508");
82          final TLE remote = new TLE("1 20061U 89044A   04013.44391333  .00000095  00000-0  10000-3 0  3242",
83                                     "2 20061  53.4233 172.2072 0234017 261.4179  95.8975  2.00577231106949");
84          states[0] = TLEPropagator.selectExtrapolator(local).propagate(date);
85          states[1] = TLEPropagator.selectExtrapolator(remote).propagate(date);
86      }
87  
88  }