RangeRateTroposphericDelayModifier.java
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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.modifiers;
import org.hipparchus.CalculusFieldElement;
import org.orekit.attitudes.InertialProvider;
import org.orekit.estimation.measurements.EstimatedMeasurement;
import org.orekit.estimation.measurements.EstimationModifier;
import org.orekit.estimation.measurements.GroundStation;
import org.orekit.estimation.measurements.RangeRate;
import org.orekit.models.earth.troposphere.DiscreteTroposphericModel;
import org.orekit.propagation.FieldSpacecraftState;
import org.orekit.propagation.SpacecraftState;
/** Class modifying theoretical range-rate measurements with tropospheric delay.
* The effect of tropospheric correction on the range-rate is directly computed
* through the computation of the tropospheric delay difference with respect to
* time.
*
* In general, for GNSS, VLBI, ... there is hardly any frequency dependence in the delay.
* For SLR techniques however, the frequency dependence is sensitive.
*
* @author Joris Olympio
* @since 8.0
*/
public class RangeRateTroposphericDelayModifier extends BaseRangeRateTroposphericDelayModifier implements EstimationModifier<RangeRate> {
/** Two-way measurement factor. */
private final double fTwoWay;
/** Constructor.
*
* @param model Tropospheric delay model appropriate for the current range-rate measurement method.
* @param tw Flag indicating whether the measurement is two-way.
*/
public RangeRateTroposphericDelayModifier(final DiscreteTroposphericModel model, final boolean tw) {
super(model);
if (tw) {
fTwoWay = 2.;
} else {
fTwoWay = 1.;
}
}
/** Compute the measurement error due to Troposphere.
* @param station station
* @param state spacecraft state
* @return the measurement error due to Troposphere
*/
@Override
public double rangeRateErrorTroposphericModel(final GroundStation station,
final SpacecraftState state) {
return fTwoWay * super.rangeRateErrorTroposphericModel(station, state);
}
/** Compute the measurement error due to Troposphere.
* @param <T> type of the element
* @param station station
* @param state spacecraft state
* @param parameters tropospheric model parameters
* @return the measurement error due to Troposphere
*/
@Override
public <T extends CalculusFieldElement<T>> T rangeRateErrorTroposphericModel(final GroundStation station,
final FieldSpacecraftState<T> state,
final T[] parameters) {
return super.rangeRateErrorTroposphericModel(station, state, parameters).multiply(fTwoWay);
}
/** {@inheritDoc} */
@Override
public void modify(final EstimatedMeasurement<RangeRate> estimated) {
final RangeRate measurement = estimated.getObservedMeasurement();
final GroundStation station = measurement.getStation();
final SpacecraftState state = estimated.getStates()[0];
RangeRateModifierUtil.modify(estimated, getTropoModel(),
new ModifierGradientConverter(state, 6, new InertialProvider(state.getFrame())),
station,
this::rangeRateErrorTroposphericModel,
this::rangeRateErrorTroposphericModel);
}
}