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.hipparchus.util.MathArrays;
20 import org.orekit.gnss.GnssSignal;
21 import org.orekit.gnss.MeasurementType;
22 import org.orekit.gnss.SatelliteSystem;
23
24 /**
25 * Wide-Lane combination.
26 * <p>
27 * This combination are used to create a signal
28 * with a significantly wide wavelength.
29 * This longer wavelength is useful for cycle-slips
30 * detection and ambiguity fixing
31 * </p>
32 * <pre>
33 * f1 * m1 - f2 * m2
34 * mWL = -----------------------
35 * f1 - f2
36 * </pre>
37 * With:
38 * <ul>
39 * <li>mWL: Wide-laning measurement.</li>
40 * <li>f1 : Frequency of the first measurement.</li>
41 * <li>m1 : First measurement.</li>
42 * <li>f2 : Frequency of the second measurement.</li>
43 * <li>m1 : Second measurement.</li>
44 * </ul>
45 * <p>
46 * Wide-Lane combination is a dual frequency combination.
47 * The two measurements shall have different frequencies but they must have the same {@link MeasurementType}.
48 * </p>
49 * @author Bryan Cazabonne
50 * @since 10.1
51 */
52 public class WideLaneCombination extends AbstractDualFrequencyCombination {
53
54 /**
55 * Package private constructor for the factory.
56 * @param system satellite system for which the combination is applied
57 */
58 WideLaneCombination(final SatelliteSystem system) {
59 super(CombinationType.WIDE_LANE, system);
60 }
61
62 /** {@inheritDoc} */
63 @Override
64 protected double getCombinedValue(final double obs1, final GnssSignal s1,
65 final double obs2, final GnssSignal s2) {
66 // Get the ration f/f0
67 final double ratioF1 = s1.getRatio();
68 final double ratioF2 = s2.getRatio();
69 // Perform combination
70 return MathArrays.linearCombination(ratioF1, obs1, -ratioF2, obs2) / (ratioF1 - ratioF2);
71 }
72
73 /** {@inheritDoc} */
74 @Override
75 protected double getCombinedFrequency(final GnssSignal s1, final GnssSignal s2) {
76 return s1.getFrequency() - s2.getFrequency();
77 }
78
79 }