1   /* Copyright 2002-2021 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  
18  package org.orekit.files.ccsds.ndm.odm.ocm;
19  
20  import java.util.List;
21  
22  import org.orekit.files.ccsds.definitions.ElementsType;
23  import org.orekit.time.AbsoluteDate;
24  import org.orekit.time.TimeStamped;
25  import org.orekit.utils.CartesianDerivativesFilter;
26  import org.orekit.utils.TimeStampedPVCoordinates;
27  import org.orekit.utils.units.Unit;
28  
29  /** Trajectory state entry.
30   * @author Luc Maisonobe
31   * @since 11.0
32   */
33  public class TrajectoryState implements TimeStamped {
34  
35      /** Type of the elements. */
36      private final ElementsType type;
37  
38      /** Entry date. */
39      private final AbsoluteDate date;
40  
41      /** Trajectory elements. */
42      private final double[] elements;
43  
44      /** Simple constructor.
45       * @param type type of the elements
46       * @param date entry date
47       * @param fields trajectory elements
48       * @param first index of first field to consider
49       * @param units units to use for parsing
50       */
51      public TrajectoryState(final ElementsType type, final AbsoluteDate date,
52                             final String[] fields, final int first, final List<Unit> units) {
53          this.type     = type;
54          this.date     = date;
55          this.elements = new double[units.size()];
56          for (int i = 0; i < elements.length; ++i) {
57              elements[i] = units.get(i).toSI(Double.parseDouble(fields[first + i]));
58          }
59      }
60  
61      /** {@inheritDoc} */
62      @Override
63      public AbsoluteDate getDate() {
64          return date;
65      }
66  
67      /** Get trajectory elements.
68       * @return trajectory elements
69       */
70      public double[] getElements() {
71          return elements.clone();
72      }
73  
74      /** Get the type of the elements.
75       * @return type of the elements
76       */
77      public ElementsType getType() {
78          return type;
79      }
80  
81      /** Get which derivatives of position are available in this state.
82       * @return a value indicating if the file contains velocity and/or acceleration
83        */
84      public CartesianDerivativesFilter getAvailableDerivatives() {
85          return type ==  ElementsType.CARTP ?
86                          CartesianDerivativesFilter.USE_P :
87                          (type == ElementsType.CARTPVA ?
88                           CartesianDerivativesFilter.USE_PVA :
89                           CartesianDerivativesFilter.USE_PV);
90      }
91  
92      /** Convert to Cartesian coordinates.
93       * @param mu gravitational parameter in m³/s²
94       * @return Cartesian coordinates
95       */
96      public TimeStampedPVCoordinates toCartesian(final double mu) {
97          return type.toCartesian(date, elements, mu);
98      }
99  
100 }