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.EstimatedMeasurement;
21  import org.orekit.estimation.measurements.EstimatedMeasurementBase;
22  import org.orekit.estimation.measurements.EstimationModifier;
23  import org.orekit.estimation.measurements.GroundStation;
24  import org.orekit.estimation.measurements.Range;
25  import org.orekit.models.earth.ionosphere.IonosphericModel;
26  import org.orekit.propagation.SpacecraftState;
27  
28  /** Class modifying theoretical range measurement with ionospheric delay.
29   * <p>
30   * The effect of ionospheric correction on the range is directly computed
31   * through the computation of the ionospheric delay.
32   * </p>
33   * <p>
34   * The ionospheric delay depends on the frequency of the signal (GNSS, VLBI, ...).
35   * For optical measurements (e.g. SLR), the ray is not affected by ionosphere charged particles.
36   * </p>
37   * <p>
38   * Since 10.0, state derivatives and ionospheric parameters derivates are computed
39   * using automatic differentiation.
40   * </p>
41   * @author Maxime Journot
42   * @author Joris Olympio
43   * @since 8.0
44   */
45  public class RangeIonosphericDelayModifier extends BaseRangeIonosphericDelayModifier implements EstimationModifier<Range> {
46  
47      /** Constructor.
48       *
49       * @param model Ionospheric delay model appropriate for the current range measurement method.
50       * @param freq frequency of the signal in Hz
51       */
52      public RangeIonosphericDelayModifier(final IonosphericModel model,
53                                           final double freq) {
54          super(model, freq);
55      }
56  
57      /** {@inheritDoc} */
58      @Override
59      public void modifyWithoutDerivatives(final EstimatedMeasurementBase<Range> estimated) {
60  
61          final Range         measurement = estimated.getObservedMeasurement();
62          final GroundStation station     = measurement.getStation();
63  
64          RangeModifierUtil.modifyWithoutDerivatives(estimated, station,
65                                                     this::rangeErrorIonosphericModel,
66                                                     this);
67  
68      }
69  
70      /** {@inheritDoc} */
71      @Override
72      public void modify(final EstimatedMeasurement<Range> estimated) {
73  
74          final Range           measurement = estimated.getObservedMeasurement();
75          final GroundStation   station     = measurement.getStation();
76          final SpacecraftState state       = estimated.getStates()[0];
77  
78          RangeModifierUtil.modify(estimated, getIonoModel(),
79                                   new ModifierGradientConverter(state, 6, new FrameAlignedProvider(state.getFrame())),
80                                   station,
81                                   this::rangeErrorIonosphericModel,
82                                   this::rangeErrorIonosphericModel,
83                                   this);
84  
85      }
86  
87  }