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3    * contributor license agreements.  See the NOTICE file distributed with
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5    * CS licenses this file to You under the Apache License, Version 2.0
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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
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16   */
17  package org.orekit.estimation.measurements.modifiers;
18  
19  import java.util.List;
20  
21  import org.hipparchus.CalculusFieldElement;
22  import org.orekit.estimation.measurements.GroundStation;
23  import org.orekit.frames.TopocentricFrame;
24  import org.orekit.models.earth.ionosphere.IonosphericModel;
25  import org.orekit.propagation.FieldSpacecraftState;
26  import org.orekit.propagation.SpacecraftState;
27  import org.orekit.utils.ParameterDriver;
28  
29  /** Base class modifying theoretical range measurement with ionospheric delay.
30   * The effect of ionospheric correction on the range is directly computed
31   * through the computation of the ionospheric delay.
32   *
33   * The ionospheric delay depends on the frequency of the signal (GNSS, VLBI, ...).
34   * For optical measurements (e.g. SLR), the ray is not affected by ionosphere charged particles.
35   * <p>
36   * Since 10.0, state derivatives and ionospheric parameters derivates are computed
37   * using automatic differentiation.
38   * </p>
39   * @author Joris Olympio
40   * @since 11.2
41   */
42  public abstract class BaseRangeIonosphericDelayModifier {
43  
44      /** Ionospheric delay model. */
45      private final IonosphericModel ionoModel;
46  
47      /** Frequency [Hz]. */
48      private final double frequency;
49  
50      /** Constructor.
51       *
52       * @param model Ionospheric delay model appropriate for the current range-rate measurement method.
53       * @param freq frequency of the signal in Hz
54       */
55      protected BaseRangeIonosphericDelayModifier(final IonosphericModel model, final double freq) {
56          this.ionoModel = model;
57          this.frequency = freq;
58      }
59  
60      /** Get the name of the effect modifying the measurement.
61       * @return name of the effect modifying the measurement
62       * @since 13.0
63       */
64      public String getEffectName() {
65          return "ionosphere";
66      }
67  
68      /** Get the ionospheric delay model.
69       * @return ionospheric delay model
70       */
71      protected IonosphericModel getIonoModel() {
72          return ionoModel;
73      }
74  
75      /** Compute the measurement error due to Ionosphere.
76       * @param station station
77       * @param state spacecraft state
78       * @return the measurement error due to Ionosphere
79       */
80      protected double rangeErrorIonosphericModel(final GroundStation station, final SpacecraftState state) {
81          // Base frame associated with the station
82          final TopocentricFrame baseFrame = station.getBaseFrame();
83          // delay in meters
84          final double delay = ionoModel.pathDelay(state, baseFrame, frequency, ionoModel.getParameters());
85          return delay;
86      }
87  
88      /** Compute the measurement error due to Ionosphere.
89       * @param <T> type of the elements
90       * @param station station
91       * @param state spacecraft state
92       * @param parameters ionospheric model parameters
93       * @return the measurement error due to Ionosphere
94       */
95      protected <T extends CalculusFieldElement<T>> T rangeErrorIonosphericModel(final GroundStation station,
96                                                                                 final FieldSpacecraftState<T> state,
97                                                                                 final T[] parameters) {
98          // Base frame associated with the station
99          final TopocentricFrame baseFrame = station.getBaseFrame();
100         // delay in meters
101         final T delay = ionoModel.pathDelay(state, baseFrame, frequency, parameters);
102         return delay;
103     }
104 
105     /** Get the drivers for this modifier parameters.
106      * @return drivers for this modifier parameters
107      */
108     public List<ParameterDriver> getParametersDrivers() {
109         return ionoModel.getParametersDrivers();
110     }
111 
112 }