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
15   * limitations under the License.
16   */
17  
18  package org.orekit.files.ccsds.ndm.odm.oem;
19  
20  import java.util.List;
21  
22  import org.orekit.files.ccsds.ndm.odm.CartesianCovariance;
23  import org.orekit.files.ccsds.section.Segment;
24  import org.orekit.files.general.EphemerisFile;
25  import org.orekit.frames.Frame;
26  import org.orekit.time.AbsoluteDate;
27  import org.orekit.utils.CartesianDerivativesFilter;
28  import org.orekit.utils.TimeStampedPVCoordinates;
29  
30  /** The Ephemerides Blocks class contain metadata, the list of ephemerides data
31   * lines and optional covariance matrices (and their metadata). The reason
32   * for which the ephemerides have been separated into blocks is that the
33   * ephemerides of two different blocks are not suited for interpolation.
34   * @author sports
35   */
36  public class OemSegment extends Segment<OemMetadata, OemData>
37      implements EphemerisFile.EphemerisSegment<TimeStampedPVCoordinates> {
38  
39      /** Gravitational parameter in m³/s². */
40      private final double mu;
41  
42      /** Simple constructor.
43       * @param metadata segment metadata
44       * @param data segment data
45       * @param mu gravitational parameter in m³/s²
46       */
47      public OemSegment(final OemMetadata metadata, final OemData data, final double mu) {
48          super(metadata, data);
49          this.mu = mu;
50      }
51  
52      /** {@inheritDoc} */
53      @Override
54      public double getMu() {
55          return mu;
56      }
57  
58      /** {@inheritDoc} */
59      @Override
60      public List<TimeStampedPVCoordinates> getCoordinates() {
61          return getData().getCoordinates();
62      }
63  
64      /** {@inheritDoc} */
65      @Override
66      public CartesianDerivativesFilter getAvailableDerivatives() {
67          return getData().getAvailableDerivatives();
68      }
69  
70      /** Get an unmodifiable view of Covariance Matrices.
71       * @return unmodifiable view of Covariance Matrices
72       */
73      public List<CartesianCovariance> getCovarianceMatrices() {
74          return getData().getCovarianceMatrices();
75      }
76  
77      /** {@inheritDoc} */
78      @Override
79      public Frame getFrame() {
80          return getMetadata().getFrame();
81      }
82  
83      /** {@inheritDoc}
84       * <p>
85       * This implementation returns {@link #getFrame() defining frame}
86       * if it is {@link Frame#isPseudoInertial() pseudo-inertial}, or
87       * its closest {@link Frame#getParent() ancestor} that is
88       * pseudo-inertial.
89       * </p>
90       */
91      @Override
92      public Frame getInertialFrame() {
93          Frame frame = getFrame();
94          while (!frame.isPseudoInertial()) {
95              frame = frame.getParent();
96          }
97          return frame;
98      }
99  
100     /** {@inheritDoc} */
101     @Override
102     public AbsoluteDate getStart() {
103         // useable start time overrides start time if it is set
104         final AbsoluteDate start = getMetadata().getUseableStartTime();
105         if (start != null) {
106             return start;
107         } else {
108             return getMetadata().getStartTime();
109         }
110     }
111 
112     /** {@inheritDoc} */
113     @Override
114     public AbsoluteDate getStop() {
115         // useable stop time overrides stop time if it is set
116         final AbsoluteDate stop = getMetadata().getUseableStopTime();
117         if (stop != null) {
118             return stop;
119         } else {
120             return getMetadata().getStopTime();
121         }
122     }
123 
124     /** {@inheritDoc} */
125     @Override
126     public int getInterpolationSamples() {
127         // From the standard it is not entirely clear how to interpret the degree.
128         return getMetadata().getInterpolationDegree() + 1;
129     }
130 
131 }