RangeRateIonosphericDelayModifier.java
/* Copyright 2002-2022 CS GROUP
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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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* 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
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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.ionosphere.IonosphericModel;
import org.orekit.propagation.FieldSpacecraftState;
import org.orekit.propagation.SpacecraftState;
/** Class modifying theoretical range-rate measurement with ionospheric delay.
* The effect of ionospheric correction on the range-rate is directly computed
* through the computation of the ionospheric delay difference with respect to
* time.
*
* The ionospheric delay depends on the frequency of the signal (GNSS, VLBI, ...).
* For optical measurements (e.g. SLR), the ray is not affected by ionosphere charged particles.
* <p>
* Since 10.0, state derivatives and ionospheric parameters derivates are computed
* using automatic differentiation.
* </p>
* @author Joris Olympio
* @since 8.0
*/
public class RangeRateIonosphericDelayModifier extends BaseRangeRateIonosphericDelayModifier implements EstimationModifier<RangeRate> {
/** Coefficient for measurment configuration (one-way, two-way). */
private final double fTwoWay;
/** Constructor.
*
* @param model Ionospheric delay model appropriate for the current range-rate measurement method.
* @param freq frequency of the signal in Hz
* @param twoWay Flag indicating whether the measurement is two-way.
*/
public RangeRateIonosphericDelayModifier(final IonosphericModel model,
final double freq, final boolean twoWay) {
super(model, freq);
if (twoWay) {
fTwoWay = 2.;
} else {
fTwoWay = 1.;
}
}
/** {@inheritDoc} */
@Override
protected double rangeRateErrorIonosphericModel(final GroundStation station, final SpacecraftState state) {
return fTwoWay * super.rangeRateErrorIonosphericModel(station, state);
}
/** {@inheritDoc} */
@Override
protected <T extends CalculusFieldElement<T>> T rangeRateErrorIonosphericModel(final GroundStation station,
final FieldSpacecraftState<T> state,
final T[] parameters) {
return super.rangeRateErrorIonosphericModel(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];
RangeModifierUtil.modify(estimated, getIonoModel(),
new ModifierGradientConverter(state, 6, new InertialProvider(state.getFrame())),
station,
this::rangeRateErrorIonosphericModel,
this::rangeRateErrorIonosphericModel);
}
}