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
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16   */
17  package org.orekit.gnss.attitude;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.orekit.frames.Frame;
21  import org.orekit.time.AbsoluteDate;
22  import org.orekit.utils.ExtendedPositionProvider;
23  import org.orekit.utils.TimeStampedAngularCoordinates;
24  import org.orekit.utils.TimeStampedFieldAngularCoordinates;
25  
26  /**
27   * Attitude providers for Beidou geostationary orbit navigation satellites.
28   * @author Luc Maisonobe Java translation
29   * @since 9.2
30   */
31  public class BeidouGeo extends AbstractGNSSAttitudeProvider {
32  
33      /** Simple constructor.
34       * @param validityStart start of validity for this provider
35       * @param validityEnd end of validity for this provider
36       * @param sun provider for Sun position
37       * @param inertialFrame inertial frame where velocity are computed
38       */
39      public BeidouGeo(final AbsoluteDate validityStart, final AbsoluteDate validityEnd,
40                       final ExtendedPositionProvider sun, final Frame inertialFrame) {
41          super(validityStart, validityEnd, sun, inertialFrame);
42      }
43  
44      /** {@inheritDoc} */
45      @Override
46      protected TimeStampedAngularCoordinates correctedYaw(final GNSSAttitudeContext context) {
47  
48          // geostationary Beidou spacecraft are always in Orbit Normal (ON) yaw
49          return context.orbitNormalYaw();
50  
51      }
52  
53      /** {@inheritDoc} */
54      @Override
55      protected  <T extends CalculusFieldElement<T>> TimeStampedFieldAngularCoordinates<T> correctedYaw(final GNSSFieldAttitudeContext<T> context) {
56  
57          // geostationary Beidou spacecraft are always in Orbit Normal (ON) yaw
58          return context.orbitNormalYaw();
59  
60      }
61  
62  }