InterSatellitesPhaseBuilder.java
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* 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
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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.generation;
import java.util.Map;
import org.hipparchus.random.CorrelatedRandomVectorGenerator;
import org.orekit.estimation.measurements.EstimationModifier;
import org.orekit.estimation.measurements.ObservableSatellite;
import org.orekit.estimation.measurements.gnss.AmbiguityCache;
import org.orekit.estimation.measurements.gnss.InterSatellitesPhase;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.sampling.OrekitStepInterpolator;
import org.orekit.time.AbsoluteDate;
import org.orekit.utils.ParameterDriver;
/** Builder for {@link InterSatellitesPhase} measurements.
* @author Bryan Cazabonne
* @since 10.3
*/
public class InterSatellitesPhaseBuilder extends AbstractMeasurementBuilder<InterSatellitesPhase> {
/** Cache for ambiguities.
* @since 12.1
*/
private final AmbiguityCache cache;
/** Wavelength of the phase observed value [m]. */
private final double wavelength;
/** Satellite which receives the signal and performs the measurement.
* @since 12.0
*/
private final ObservableSatellite local;
/** Satellite which simply emits the signal.
* @since 12.0
*/
private final ObservableSatellite remote;
/** Simple constructor.
* @param noiseSource noise source, may be null for generating perfect measurements
* @param local satellite which receives the signal and performs the measurement
* @param remote satellite which simply emits the signal
* @param wavelength phase observed value wavelength (m)
* @param sigma theoretical standard deviation
* @param baseWeight base weight
* @deprecated as of 12.1, replaced by {@link #InterSatellitesPhaseBuilder(CorrelatedRandomVectorGenerator,
* ObservableSatellite, ObservableSatellite, double, double, double, AmbiguityCache)}
*/
@Deprecated
public InterSatellitesPhaseBuilder(final CorrelatedRandomVectorGenerator noiseSource,
final ObservableSatellite local, final ObservableSatellite remote,
final double wavelength, final double sigma, final double baseWeight) {
this(noiseSource, local, remote, wavelength, sigma, baseWeight,
AmbiguityCache.DEFAULT_CACHE);
}
/** Simple constructor.
* @param noiseSource noise source, may be null for generating perfect measurements
* @param local satellite which receives the signal and performs the measurement
* @param remote satellite which simply emits the signal
* @param wavelength phase observed value wavelength (m)
* @param sigma theoretical standard deviation
* @param baseWeight base weight
* @param cache from which ambiguity drive should come
* @since 12.1
*/
public InterSatellitesPhaseBuilder(final CorrelatedRandomVectorGenerator noiseSource,
final ObservableSatellite local, final ObservableSatellite remote,
final double wavelength, final double sigma, final double baseWeight,
final AmbiguityCache cache) {
super(noiseSource, sigma, baseWeight, local, remote);
this.cache = cache;
this.wavelength = wavelength;
this.local = local;
this.remote = remote;
}
/** {@inheritDoc} */
@Override
public InterSatellitesPhase build(final AbsoluteDate date, final Map<ObservableSatellite, OrekitStepInterpolator> interpolators) {
final double sigma = getTheoreticalStandardDeviation()[0];
final double baseWeight = getBaseWeight()[0];
final SpacecraftState[] relevant = new SpacecraftState[] {
interpolators.get(local).getInterpolatedState(date),
interpolators.get(remote).getInterpolatedState(date)
};
// create a dummy measurement
final InterSatellitesPhase dummy = new InterSatellitesPhase(local, remote, relevant[0].getDate(),
Double.NaN, wavelength, sigma, baseWeight,
cache);
for (final EstimationModifier<InterSatellitesPhase> modifier : getModifiers()) {
dummy.addModifier(modifier);
}
// set a reference date for parameters missing one
for (final ParameterDriver driver : dummy.getParametersDrivers()) {
if (driver.getReferenceDate() == null) {
final AbsoluteDate start = getStart();
final AbsoluteDate end = getEnd();
driver.setReferenceDate(start.durationFrom(end) <= 0 ? start : end);
}
}
// estimate the perfect value of the measurement
double phase = dummy.estimateWithoutDerivatives(relevant).getEstimatedValue()[0];
// add the noise
final double[] noise = getNoise();
if (noise != null) {
phase += noise[0];
}
// generate measurement
final InterSatellitesPhase measurement = new InterSatellitesPhase(local, remote, relevant[0].getDate(),
phase, wavelength, sigma, baseWeight,
cache);
for (final EstimationModifier<InterSatellitesPhase> modifier : getModifiers()) {
measurement.addModifier(modifier);
}
return measurement;
}
}