NarrowLaneCombination.java
/* Copyright 2002-2024 CS GROUP
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* CS licenses this file to You under the Apache License, Version 2.0
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*
* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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package org.orekit.estimation.measurements.gnss;
import org.hipparchus.util.MathArrays;
import org.orekit.gnss.Frequency;
import org.orekit.gnss.MeasurementType;
import org.orekit.gnss.SatelliteSystem;
/**
* Narrow-Lane combination.
* <p>
* This combination create signal with a narrow wavelength.
* The signal in this combination has a lower noise than each
* separated separeted component.
* </p>
* <pre>
* f1 * m1 + f2 * m2
* mNL = -----------------------
* f1 + f2
* </pre>
* With:
* <ul>
* <li>mNL : Narrow-laning measurement.</li>
* <li>f1 : Frequency of the first measurement.</li>
* <li>pr1 : First measurement.</li>
* <li>f2 : Frequency of the second measurement.</li>
* <li>m1 : Second measurement.</li>
* </ul>
* <p>
* Narrow-Lane combination is a dual frequency combination.
* The two measurements shall have different frequencies but they must have the same {@link MeasurementType}.
* </p>
* @author Bryan Cazabonne
* @since 10.1
*/
public class NarrowLaneCombination extends AbstractDualFrequencyCombination {
/**
* Package private constructor for the factory.
* @param system satellite system for which the combination is applied
*/
NarrowLaneCombination(final SatelliteSystem system) {
super(CombinationType.NARROW_LANE, system);
}
/** {@inheritDoc} */
@Override
protected double getCombinedValue(final double obs1, final Frequency f1,
final double obs2, final Frequency f2) {
// Get the ration f/f0
final double ratioF1 = f1.getRatio();
final double ratioF2 = f2.getRatio();
// Perform combination
return MathArrays.linearCombination(ratioF1, obs1, ratioF2, obs2) / (ratioF1 + ratioF2);
}
/** {@inheritDoc} */
@Override
protected double getCombinedFrequency(final Frequency f1, final Frequency f2) {
return f1.getMHzFrequency() + f2.getMHzFrequency();
}
}