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  import org.orekit.gnss.SatelliteSystem;
20  
21  /**
22   * GRoup And Phase Ionospheric Calibration (GRAPHIC) combination.
23   * <p>
24   * This combination is a ionosphere-free single frequency
25   * combination of measurements.
26   * </p>
27   * <pre>
28   *    mf =  0.5 * (Φf + Rf)
29   * </pre>
30   * With:
31   * <ul>
32   * <li>mf : GRAPHIC measurement.</li>
33   * <li>Φf : Phase measurement.</li>
34   * <li>Rf : Code measurement.</li>
35   * <li>f  : Frequency.</li>
36   * </ul>
37   * @author Bryan Cazabonne
38   * @since 10.1
39   */
40  public class GRAPHICCombination extends AbstractSingleFrequencyCombination {
41  
42      /**
43       * Package private constructor for the factory.
44       * @param system satellite system for which the combination is applied
45       */
46      GRAPHICCombination(final SatelliteSystem system) {
47          super(CombinationType.GRAPHIC, system);
48      }
49  
50      /** {@inheritDoc} */
51      @Override
52      protected double getCombinedValue(final double phase, final double pseudoRange) {
53          // Combination does not depend on the frequency
54          return 0.5 * (phase + pseudoRange);
55      }
56  
57  }