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.orekit.frames.Frame;
21  import org.orekit.time.AbsoluteDate;
22  
23  /** Provider using simple {@link PVCoordinates#shiftedBy(double)}  shiftedBy} and frame transforms for evolution.
24   * @author Luc Maisonobe
25   * @since 12.1
26   */
27  public class ShiftingPVCoordinatesProvider implements PVCoordinatesProvider {
28  
29      /** Reference coordinates. */
30      private final TimeStampedPVCoordinates referencePV;
31  
32      /** Frame in which {@link #referencePV} is defined. */
33      private final Frame referenceFrame;
34  
35      /** Simple constructor.
36       * @param referencePV reference coordinates
37       * @param referenceFrame frame in which {@code reference} is defined
38       */
39      public ShiftingPVCoordinatesProvider(final TimeStampedPVCoordinates referencePV,
40                                           final Frame referenceFrame) {
41          this.referencePV    = referencePV;
42          this.referenceFrame = referenceFrame;
43      }
44  
45      /** {@inheritDoc} */
46      @Override
47      public TimeStampedPVCoordinates getPVCoordinates(final AbsoluteDate date,
48                                                       final Frame frame) {
49          final TimeStampedPVCoordinates shifted = referencePV.shiftedBy(date.durationFrom(referencePV));
50          return referenceFrame.getTransformTo(frame, date).transformPVCoordinates(shifted);
51      }
52  
53  }