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.sinex;
19  
20  import org.orekit.gnss.ObservationType;
21  import org.orekit.time.AbsoluteDate;
22  import org.orekit.utils.TimeSpanMap;
23  
24  import java.util.HashMap;
25  import java.util.HashSet;
26  
27  /** Container for observation-specific signal bias for a single link endpoint
28   * (either emitter or receiver).
29   * <p>
30   * This class is made to handle both station and satellite OSB data.
31   * Bias values are stored in TimeSpanMaps associated with a given
32   * observation type. Those TimeSpanMaps are stored in a Map, which
33   * associate an observation code to a TimeSpanMap of double values.
34   * </p>
35   * @author Louis Aucouturier
36   * @author Luc Maisonobe
37   * @since 13.0
38   */
39  public class ObservableSpecificSignalBias {
40  
41      /** Set of observation types available for the satellite. */
42      private final HashSet<ObservationType> observationSets;
43  
44      /** Set of biases, identifiable by observation types,
45       * each containing the corresponding TimeSpanMap of biases.
46       */
47      private final HashMap<ObservationType, TimeSpanMap<Double>> biases;
48  
49      /** Simple constructor.
50       */
51      public ObservableSpecificSignalBias() {
52          this.observationSets = new HashSet<>();
53          this.biases          = new HashMap<>();
54      }
55  
56      /** Add a bias.
57       * @param obs observation used for the OSB computation
58       * @param spanBegin beginning of the validity span for this bias value
59       * @param spanEnd end of the validity span for this bias value
60       * @param biasValue Observable-specific Signal Bias value (meters for code and cycle for phase)
61       */
62      public void addBias(final ObservationType obs,
63                          final AbsoluteDate spanBegin, final AbsoluteDate spanEnd,
64                          final double biasValue) {
65  
66          // If not present add a new bias to the map, identified by the Observation type.
67          // Then add the bias value and validity period.
68          if (observationSets.add(obs)) {
69              biases.put(obs, new TimeSpanMap<>(null));
70          }
71  
72          biases.get(obs).addValidBetween(biasValue, spanBegin, spanEnd);
73      }
74  
75      /** Get the value of the Observable-specific Signal Bias for a given observation type at a given date.
76       * @param obs observation type
77       * @param date date at which to obtain the Observable-specific Signal Bias
78       * @return the value of the Observable-specific Signal Bias (meters for code and cycle for phase)
79       */
80      public double getBias(final ObservationType obs, final AbsoluteDate date) {
81          return getTimeSpanMap(obs).get(date);
82      }
83  
84      /** Get all available observation types for the satellite.
85       * @return Observation types obtained.
86       */
87      public HashSet<ObservationType> getAvailableObservations() {
88          return observationSets;
89      }
90  
91      /** Get the minimum valid date for a given observation type.
92       * @param obs observation type
93       * @return minimum valid date for the observation pair
94       */
95      public AbsoluteDate getMinimumValidDateForObservation(final ObservationType obs) {
96          return getTimeSpanMap(obs).getFirstTransition().getDate();
97      }
98  
99      /** Get the maximum valid date for a given observation type.
100      * @param obs observation type
101      * @return maximum valid date for the observation pair
102      */
103     public AbsoluteDate getMaximumValidDateForObservation(final ObservationType obs) {
104         return getTimeSpanMap(obs).getLastTransition().getDate();
105     }
106 
107     /** Get the TimeSpanMap object for a given observation type,
108      * for further operation on the object directly.
109      *
110      * @param obs observation type
111      * @return the time span map for a given observation code pair
112      */
113     private TimeSpanMap<Double> getTimeSpanMap(final ObservationType obs) {
114         return biases.get(obs);
115     }
116 
117 }