PhaseAmbiguityModifier.java
/* Copyright 2002-2019 CS Systèmes d'Information
* Licensed to CS Systèmes d'Information (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.orekit.estimation.measurements.modifiers;
import java.util.Collections;
import java.util.List;
import org.hipparchus.util.FastMath;
import org.orekit.estimation.measurements.EstimatedMeasurement;
import org.orekit.estimation.measurements.EstimationModifier;
import org.orekit.estimation.measurements.Phase;
import org.orekit.utils.ParameterDriver;
/** Class modifying theoretical phase measurement with ambiguity.
*
* @author Luc Maisonobe
* @since 9.2
*/
public class PhaseAmbiguityModifier implements EstimationModifier<Phase> {
/** Ambiguity scale factor.
* <p>
* We use a power of 2 to avoid numeric noise introduction
* in the multiplications/divisions sequences.
* </p>
*/
private static final double AMBIGUITY_SCALE = FastMath.scalb(1.0, 26);
/** Ambiguity parameter. */
private final ParameterDriver ambiguity;
/** Constructor.
* <p>
* It is expected that many different ambiguities will be used at the
* same time during an orbit determination, therefore they are keyed
* using a simple integer. All ambiguities using the same key will
* be enforced to be equal. It is the responsibility of the caller to
* use a proper counter to manage the ambiguities properly.
* </p>
* @param key key to identify the ambiguity
* @param ambiguity initial value of ambiguity
*/
public PhaseAmbiguityModifier(final int key, final double ambiguity) {
this.ambiguity = new ParameterDriver("amgiguity-" + key,
ambiguity, AMBIGUITY_SCALE,
Double.NEGATIVE_INFINITY,
Double.POSITIVE_INFINITY);
}
/** {@inheritDoc} */
@Override
public List<ParameterDriver> getParametersDrivers() {
return Collections.singletonList(ambiguity);
}
@Override
public void modify(final EstimatedMeasurement<Phase> estimated) {
// apply the ambiguity to the measurement value
final double[] value = estimated.getEstimatedValue();
value[0] += ambiguity.getValue();
if (ambiguity.isSelected()) {
// add the partial derivatives
estimated.setParameterDerivatives(ambiguity, 1.0);
}
estimated.setEstimatedValue(value);
}
}