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  package org.orekit.estimation.measurements.gnss;
18  
19  /** Ambiguity acceptance test based on a ratio of the two best candidates.
20   * @see AmbiguitySolver
21   * @author Luc Maisonobe
22   * @since 10.0
23   */
24  public class SimpleRatioAmbiguityAcceptance implements AmbiguityAcceptance {
25  
26      /** Number of candidate solutions. */
27      private static final int NB_CANDIDATES = 2;
28  
29      /** Acceptance ratio for {@code candidate[0]/candidate[1]}. */
30      private final double ratio;
31  
32      /** Simple constructor.
33       * @param ratio acceptance ratio for {@code candidate[0]/candidate[1]},
34       * typically {@code 1.0/2.0} or {@code 1.0/3.0}
35       */
36      public SimpleRatioAmbiguityAcceptance(final double ratio) {
37          this.ratio = ratio;
38      }
39  
40      /** {@inheritDoc} */
41      @Override
42      public int numberOfCandidates() {
43          return NB_CANDIDATES;
44      }
45  
46      /** {@inheritDoc}
47       * <p>
48       * If the ratio {@code candidate[0]/candidate[1]} is smaller or
49       * equal to the ratio given at construction, then {@code candidate[0]}
50       * will be accepted
51       * </p>
52       */
53      @Override
54      public IntegerLeastSquareSolution accept(final IntegerLeastSquareSolution[] candidates) {
55          if (candidates[0].getSquaredDistance() / candidates[1].getSquaredDistance() <= ratio) {
56              return candidates[0];
57          } else {
58              return null;
59          }
60      }
61  
62  }