1   /* Copyright 2002-2025 Bryan Cazabonne
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    * Bryan Cazabonne 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.generation;
18  
19  import org.hipparchus.random.CorrelatedRandomVectorGenerator;
20  import org.orekit.estimation.measurements.FDOA;
21  import org.orekit.estimation.measurements.GroundStation;
22  import org.orekit.estimation.measurements.ObservableSatellite;
23  import org.orekit.propagation.sampling.OrekitStepInterpolator;
24  import org.orekit.time.AbsoluteDate;
25  
26  import java.util.Map;
27  
28  /** Builder for {@link FDOA} measurements.
29   * @author Bryan Cazabonne
30   * @since 12.0
31   */
32  public class FDOABuilder extends AbstractMeasurementBuilder<FDOA> {
33  
34      /** Prime ground station. */
35      private final GroundStation primeStation;
36  
37      /** Second ground station. */
38      private final GroundStation secondStation;
39  
40      /** Centre frequency of the signal emitted from the satellite. */
41      private final double centreFrequency;
42  
43      /** Simple constructor.
44       * @param noiseSource noise source, may be null for generating perfect measurements
45       * @param primeStation ground station that gives the date of the measurement
46       * @param secondStation ground station that gives the measurement
47       * @param centreFrequency satellite emitter frequency
48       * @param sigma theoretical standard deviation
49       * @param baseWeight base weight
50       * @param satellite satellite related to this builder
51       */
52      public FDOABuilder(final CorrelatedRandomVectorGenerator noiseSource,
53                         final GroundStation primeStation,
54                         final GroundStation secondStation,
55                         final double centreFrequency,
56                         final double sigma, final double baseWeight,
57                         final ObservableSatellite satellite) {
58          super(noiseSource, sigma, baseWeight, satellite);
59          this.primeStation    = primeStation;
60          this.secondStation   = secondStation;
61          this.centreFrequency = centreFrequency;
62      }
63  
64      /** {@inheritDoc} */
65      @Override
66      protected FDOA buildObserved(final AbsoluteDate date,
67                                   final Map<ObservableSatellite, OrekitStepInterpolator> interpolators) {
68          return new FDOA(primeStation, secondStation, centreFrequency,
69                          date, Double.NaN,
70                          getTheoreticalStandardDeviation()[0],
71                          getBaseWeight()[0], getSatellites()[0]);
72      }
73  
74  }