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.orekit.attitudes.FrameAlignedProvider;
20  import org.orekit.estimation.measurements.BistaticRangeRate;
21  import org.orekit.estimation.measurements.EstimatedMeasurement;
22  import org.orekit.estimation.measurements.EstimatedMeasurementBase;
23  import org.orekit.estimation.measurements.EstimationModifier;
24  import org.orekit.estimation.measurements.GroundStation;
25  import org.orekit.models.earth.troposphere.TroposphericModel;
26  import org.orekit.propagation.SpacecraftState;
27  
28  /** Class modifying theoretical bistatic range-rate measurements with tropospheric delay.
29   * <p>
30   * The effect of tropospheric correction on the bistatic range-rate is directly computed
31   * through the computation of the tropospheric delay difference with respect to time.
32   * </p><p>
33   * Tropospheric delay is not frequency dependent for signals up to 15 GHz.
34   * </p>
35   * @author Pascal Parraud
36   * @since 11.2
37   */
38  public class BistaticRangeRateTroposphericDelayModifier
39      extends BaseRangeRateTroposphericDelayModifier implements EstimationModifier<BistaticRangeRate> {
40  
41      /** Constructor.
42       *
43       * @param model Tropospheric delay model appropriate for the current range-rate measurement method.
44       * @since 12.1
45       */
46      public BistaticRangeRateTroposphericDelayModifier(final TroposphericModel model) {
47          super(model);
48      }
49  
50      /** {@inheritDoc} */
51      @Override
52      public void modifyWithoutDerivatives(final EstimatedMeasurementBase<BistaticRangeRate> estimated) {
53  
54          final BistaticRangeRate measurement = estimated.getObservedMeasurement();
55          final GroundStation     emitter     = measurement.getEmitterStation();
56          final GroundStation     receiver    = measurement.getReceiverStation();
57  
58          BistaticModifierUtil.modify(estimated, emitter, receiver,
59                                      this::rangeRateErrorTroposphericModel, this);
60  
61      }
62  
63      /** {@inheritDoc} */
64      @Override
65      public void modify(final EstimatedMeasurement<BistaticRangeRate> estimated) {
66  
67          final BistaticRangeRate measurement = estimated.getObservedMeasurement();
68          final GroundStation     emitter     = measurement.getEmitterStation();
69          final GroundStation     receiver    = measurement.getReceiverStation();
70          final SpacecraftState   state       = estimated.getStates()[0];
71  
72          BistaticModifierUtil.modify(estimated, getTropoModel(),
73                                      new ModifierGradientConverter(state, 6, new FrameAlignedProvider(state.getFrame())),
74                                      emitter, receiver,
75                                      this::rangeRateErrorTroposphericModel,
76                                      this::rangeRateErrorTroposphericModel,
77                                      this);
78  
79      }
80  
81  }