RangeBuilder.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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*
* http://www.apache.org/licenses/LICENSE-2.0
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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.GroundStation;
import org.orekit.estimation.measurements.ObservableSatellite;
import org.orekit.estimation.measurements.Range;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.sampling.OrekitStepInterpolator;
import org.orekit.time.AbsoluteDate;
import org.orekit.utils.ParameterDriver;
/** Builder for {@link Range} measurements.
* @author Luc Maisonobe
* @since 9.3
*/
public class RangeBuilder extends AbstractMeasurementBuilder<Range> {
/** Ground station from which measurement is performed. */
private final GroundStation station;
/** Flag indicating whether it is a two-way measurement. */
private final boolean twoway;
/** 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 twoWay flag indicating whether it is a two-way measurement
* @param sigma theoretical standard deviation
* @param baseWeight base weight
* @param satellite satellite related to this builder
*/
public RangeBuilder(final CorrelatedRandomVectorGenerator noiseSource,
final GroundStation station, final boolean twoWay,
final double sigma, final double baseWeight,
final ObservableSatellite satellite) {
super(noiseSource, sigma, baseWeight, satellite);
this.station = station;
this.twoway = twoWay;
this.satellite = satellite;
}
/** {@inheritDoc} */
@Override
public Range 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(satellite).getInterpolatedState(date) };
// create a dummy measurement
final Range dummy = new Range(station, twoway, relevant[0].getDate(), Double.NaN, sigma, baseWeight, satellite);
for (final EstimationModifier<Range> 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 range = dummy.estimateWithoutDerivatives(relevant).getEstimatedValue()[0];
// add the noise
final double[] noise = getNoise();
if (noise != null) {
range += noise[0];
}
// generate measurement
final Range measurement = new Range(station, twoway, relevant[0].getDate(), range, sigma, baseWeight, satellite);
for (final EstimationModifier<Range> modifier : getModifiers()) {
measurement.addModifier(modifier);
}
return measurement;
}
}