1   /* Copyright 2022-2025 Luc Maisonobe
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  
18  package org.orekit.utils;
19  
20  import org.hipparchus.CalculusFieldElement;
21  import org.orekit.frames.Frame;
22  import org.orekit.time.FieldAbsoluteDate;
23  
24  /** Provider using simple {@link FieldPVCoordinates#shiftedBy(CalculusFieldElement)} shiftedBy} and frame transforms for evolution.
25   * @param <T> the type of the field elements
26   * @author Luc Maisonobe
27   * @since 12.1
28   */
29  public class FieldShiftingPVCoordinatesProvider<T extends CalculusFieldElement<T>>
30      implements FieldPVCoordinatesProvider<T> {
31  
32      /** Reference coordinates. */
33      private final TimeStampedFieldPVCoordinates<T> referencePV;
34  
35      /** Frame in which {@link #referencePV} is defined. */
36      private final Frame referenceFrame;
37  
38      /** Simple constructor.
39       * @param referencePV reference coordinates
40       * @param referenceFrame frame in which {@code reference} is defined
41       */
42      public FieldShiftingPVCoordinatesProvider(final TimeStampedFieldPVCoordinates<T> referencePV,
43                                                final Frame referenceFrame) {
44          this.referencePV    = referencePV;
45          this.referenceFrame = referenceFrame;
46      }
47  
48      /** {@inheritDoc} */
49      @Override
50      public TimeStampedFieldPVCoordinates<T> getPVCoordinates(final FieldAbsoluteDate<T> date,
51                                                               final Frame frame) {
52          final TimeStampedFieldPVCoordinates<T> shifted = referencePV.shiftedBy(date.durationFrom(referencePV));
53          return referenceFrame.getTransformTo(frame, date).transformPVCoordinates(shifted);
54      }
55  
56  }