1   /* Copyright 2002-2023 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.time;
18  
19  import org.hipparchus.CalculusFieldElement;
20  
21  /** GLONASS time scale.
22   * <p>By convention, TGLONASS = UTC + 3 hours.</p>
23   * <p>The time scale is defined in <a
24   * href="http://www.spacecorp.ru/upload/iblock/1c4/cgs-aaixymyt%205.1%20ENG%20v%202014.02.18w.pdf">
25   * Global Navigation Sattelite System GLONASS - Interface Control document</a>, version 5.1 2008
26   * (the typo in the title is in the original document title).
27   * </p>
28   * <p>This is intended to be accessed thanks to {@link TimeScales},
29   * so there is no public constructor.</p>
30   * @author Luc Maisonobe
31   * @see AbsoluteDate
32   */
33  public class GLONASSScale implements TimeScale {
34  
35      /** Serializable UID. */
36      private static final long serialVersionUID = 20160331L;
37  
38      /** Constant offset with respect to UTC (3 hours). */
39      private static final double OFFSET = 10800;
40  
41      /** UTC time scale. */
42      private final UTCScale utc;
43  
44      /** Package private constructor for the factory.
45       * @param utc underlying UTC scale
46       */
47      GLONASSScale(final UTCScale utc) {
48          this.utc = utc;
49      }
50  
51      /** {@inheritDoc} */
52      @Override
53      public double offsetFromTAI(final AbsoluteDate date) {
54          return OFFSET + utc.offsetFromTAI(date);
55      }
56  
57      /** {@inheritDoc} */
58      @Override
59      public <T extends CalculusFieldElement<T>> T offsetFromTAI(final FieldAbsoluteDate<T> date) {
60          return utc.offsetFromTAI(date).add(OFFSET);
61      }
62  
63      /** {@inheritDoc} */
64      @Override
65      public double offsetToTAI(final DateComponents date, final TimeComponents time) {
66          final DateTimeComponents utcComponents =
67                          new DateTimeComponents(new DateTimeComponents(date, time), -OFFSET);
68          return utc.offsetToTAI(utcComponents.getDate(), utcComponents.getTime()) - OFFSET;
69      }
70  
71      /** {@inheritDoc} */
72      @Override
73      public boolean insideLeap(final AbsoluteDate date) {
74          return utc.insideLeap(date);
75      }
76  
77      /** {@inheritDoc} */
78      @Override
79      public <T extends CalculusFieldElement<T>> boolean insideLeap(final FieldAbsoluteDate<T> date) {
80          return utc.insideLeap(date);
81      }
82  
83      /** {@inheritDoc} */
84      @Override
85      public int minuteDuration(final AbsoluteDate date) {
86          return utc.minuteDuration(date);
87      }
88  
89      /** {@inheritDoc} */
90      @Override
91      public <T extends CalculusFieldElement<T>> int minuteDuration(final FieldAbsoluteDate<T> date) {
92          return utc.minuteDuration(date);
93      }
94  
95      /** {@inheritDoc} */
96      @Override
97      public double getLeap(final AbsoluteDate date) {
98          return utc.getLeap(date);
99      }
100 
101     /** {@inheritDoc} */
102     @Override
103     public <T extends CalculusFieldElement<T>> T getLeap(final FieldAbsoluteDate<T> date) {
104         return utc.getLeap(date);
105     }
106 
107     /** {@inheritDoc} */
108     public String getName() {
109         return "GLONASS";
110     }
111 
112     /** {@inheritDoc} */
113     public String toString() {
114         return getName();
115     }
116 
117 }