1   /* Copyright 2002-2025 Mark Rutten
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    * Mark Rutten 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.BistaticRange;
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 measurement with tropospheric delay.
29   * <p>
30   * The effect of tropospheric correction on the range is directly computed
31   * through the computation of the tropospheric delay.
32   * </p>
33   * <p>
34   * In general, for GNSS, VLBI, ... there is hardly any frequency dependence in the delay.
35   * For SLR techniques however, the frequency dependence is sensitive.
36   * </p>
37   *
38   * @author Maxime Journot
39   * @author Joris Olympio
40   * @author Mark Rutten
41   * @since 11.2
42   */
43  public class BistaticRangeTroposphericDelayModifier extends BaseRangeTroposphericDelayModifier implements EstimationModifier<BistaticRange> {
44  
45      /** Constructor.
46       *
47       * @param model Tropospheric delay model appropriate for the current range measurement method.
48       * @since 12.1
49       */
50      public BistaticRangeTroposphericDelayModifier(final TroposphericModel model) {
51          super(model);
52      }
53  
54      /** {@inheritDoc} */
55      @Override
56      public void modifyWithoutDerivatives(final EstimatedMeasurementBase<BistaticRange> estimated) {
57          final BistaticRange measurement = estimated.getObservedMeasurement();
58          final GroundStation emitter     = measurement.getEmitterStation();
59          final GroundStation receiver    = measurement.getReceiverStation();
60  
61          BistaticModifierUtil.modify(estimated, emitter, receiver,
62                                      this::rangeErrorTroposphericModel, this);
63  
64      }
65  
66      /** {@inheritDoc} */
67      @Override
68      public void modify(final EstimatedMeasurement<BistaticRange> estimated) {
69          final BistaticRange measurement = estimated.getObservedMeasurement();
70          final GroundStation emitter     = measurement.getEmitterStation();
71          final GroundStation receiver    = measurement.getReceiverStation();
72          final SpacecraftState state     = estimated.getStates()[0];
73  
74          BistaticModifierUtil.modify(estimated, getTropoModel(),
75                                      new ModifierGradientConverter(state, 6, new FrameAlignedProvider(state.getFrame())),
76                                      emitter, receiver,
77                                      this::rangeErrorTroposphericModel,
78                                      this::rangeErrorTroposphericModel,
79                                      this);
80  
81      }
82  
83  }