1   /* Copyright 2002-2024 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.frames;
18  
19  import org.hipparchus.CalculusFieldElement;
20  import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
21  import org.hipparchus.geometry.euclidean.threed.Vector3D;
22  import org.orekit.bodies.CelestialBody;
23  import org.orekit.time.AbsoluteDate;
24  import org.orekit.time.FieldAbsoluteDate;
25  import org.orekit.utils.FieldPVCoordinates;
26  import org.orekit.utils.PVCoordinates;
27  
28  /** Transform provider for the inertial Barycentered frame.
29   * @author Vincent Mouraux
30   * @since 10.2
31   */
32  class TwoBodiesBaryTransformProvider implements TransformProvider {
33  
34      /** Serializable UID.*/
35      private static final long serialVersionUID = 20190726L;
36  
37      /** Frame for results. Always defined as primaryBody's inertially oriented frame.*/
38      private final Frame frame;
39  
40      /** Celestial body with bigger mass, m1. */
41      private final CelestialBody primaryBody;
42  
43      /** Celestial body with smaller mass, m2. */
44      private final CelestialBody secondaryBody;
45  
46  
47      /** Simple constructor.
48       * @param primaryBody Primary body.
49       * @param secondaryBody Secondary body.
50       */
51      TwoBodiesBaryTransformProvider(final CelestialBody primaryBody, final CelestialBody secondaryBody) {
52          this.primaryBody = primaryBody;
53          this.secondaryBody = secondaryBody;
54          this.frame = primaryBody.getInertiallyOrientedFrame();
55      }
56  
57      /** {@inheritDoc} */
58      @Override
59      public Transform getTransform(final AbsoluteDate date) {
60          final PVCoordinates pv21 = secondaryBody.getPVCoordinates(date, frame);
61          final double massRatio = secondaryBody.getGM() / (primaryBody.getGM() + secondaryBody.getGM());
62          final Vector3D translation = pv21.getPosition().scalarMultiply(massRatio).negate();
63          return new Transform(date, translation);
64      }
65  
66      /** {@inheritDoc} */
67      @Override
68      public <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date) {
69          final FieldPVCoordinates<T> pv21        = secondaryBody.getPVCoordinates(date, frame);
70          final double massRatio = secondaryBody.getGM() / (primaryBody.getGM() + secondaryBody.getGM());
71          final FieldVector3D<T> translation = pv21.getPosition().scalarMultiply(massRatio).negate();
72          return new FieldTransform<>(date, translation);
73      }
74  }