AngularRaDecBuilder.java
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* 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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*
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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.AngularRaDec;
import org.orekit.estimation.measurements.EstimationModifier;
import org.orekit.estimation.measurements.GroundStation;
import org.orekit.estimation.measurements.ObservableSatellite;
import org.orekit.frames.Frame;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.sampling.OrekitStepInterpolator;
import org.orekit.time.AbsoluteDate;
import org.orekit.utils.ParameterDriver;
/** Builder for {@link AngularRaDec} measurements.
* @author Luc Maisonobe
* @since 9.3
*/
public class AngularRaDecBuilder extends AbstractMeasurementBuilder<AngularRaDec> {
/** Ground station from which measurement is performed. */
private final GroundStation station;
/** Reference frame in which the right ascension - declination angles are given. */
private final Frame referenceFrame;
/** Satellite related to this builder.
* @since 12.0
*/
private final ObservableSatellite satellite;
/** Simple constructor.
* @param noiseSource noise source, may be null for generating perfect measurements
* @param station ground station from which measurement is performed
* @param referenceFrame Reference frame in which the right ascension - declination angles are given
* @param sigma theoretical standard deviation
* @param baseWeight base weight
* @param satellite satellite related to this builder
*/
public AngularRaDecBuilder(final CorrelatedRandomVectorGenerator noiseSource,
final GroundStation station, final Frame referenceFrame,
final double[] sigma, final double[] baseWeight,
final ObservableSatellite satellite) {
super(noiseSource, sigma, baseWeight, satellite);
this.station = station;
this.referenceFrame = referenceFrame;
this.satellite = satellite;
}
/** {@inheritDoc} */
@Override
public AngularRaDec build(final AbsoluteDate date, final Map<ObservableSatellite, OrekitStepInterpolator> interpolators) {
final double[] sigma = getTheoreticalStandardDeviation();
final double[] baseWeight = getBaseWeight();
final SpacecraftState[] relevant = new SpacecraftState[] { interpolators.get(satellite).getInterpolatedState(date) };
// create a dummy measurement
final AngularRaDec dummy = new AngularRaDec(station, referenceFrame, relevant[0].getDate(),
new double[] {
0.0, 0.0
}, sigma, baseWeight, satellite);
for (final EstimationModifier<AngularRaDec> 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
final double[] angular = dummy.estimateWithoutDerivatives(relevant).getEstimatedValue();
// add the noise
final double[] noise = getNoise();
if (noise != null) {
angular[0] += noise[0];
angular[1] += noise[1];
}
// generate measurement
final AngularRaDec measurement = new AngularRaDec(station, referenceFrame, relevant[0].getDate(),
angular, sigma, baseWeight, satellite);
for (final EstimationModifier<AngularRaDec> modifier : getModifiers()) {
measurement.addModifier(modifier);
}
return measurement;
}
}