RangeIonosphericDelayModifier.java

/* Copyright 2002-2024 CS GROUP
 * Licensed to CS GROUP (CS) under one or more
 * 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
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
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package org.orekit.estimation.measurements.modifiers;

import org.orekit.attitudes.FrameAlignedProvider;
import org.orekit.estimation.measurements.EstimatedMeasurement;
import org.orekit.estimation.measurements.EstimatedMeasurementBase;
import org.orekit.estimation.measurements.EstimationModifier;
import org.orekit.estimation.measurements.GroundStation;
import org.orekit.estimation.measurements.Range;
import org.orekit.models.earth.ionosphere.IonosphericModel;
import org.orekit.propagation.SpacecraftState;

/** Class modifying theoretical range measurement with ionospheric delay.
 * <p>
 * The effect of ionospheric correction on the range is directly computed
 * through the computation of the ionospheric delay.
 * </p>
 * <p>
 * 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>
 * <p>
 * Since 10.0, state derivatives and ionospheric parameters derivates are computed
 * using automatic differentiation.
 * </p>
 * @author Maxime Journot
 * @author Joris Olympio
 * @since 8.0
 */
public class RangeIonosphericDelayModifier extends BaseRangeIonosphericDelayModifier implements EstimationModifier<Range> {

    /** Constructor.
     *
     * @param model Ionospheric delay model appropriate for the current range measurement method.
     * @param freq frequency of the signal in Hz
     */
    public RangeIonosphericDelayModifier(final IonosphericModel model,
                                         final double freq) {
        super(model, freq);
    }

    /** {@inheritDoc} */
    @Override
    public void modifyWithoutDerivatives(final EstimatedMeasurementBase<Range> estimated) {

        final Range         measurement = estimated.getObservedMeasurement();
        final GroundStation station     = measurement.getStation();

        RangeModifierUtil.modifyWithoutDerivatives(estimated, station,
                                                   this::rangeErrorIonosphericModel,
                                                   this);

    }

    /** {@inheritDoc} */
    @Override
    public void modify(final EstimatedMeasurement<Range> estimated) {

        final Range           measurement = estimated.getObservedMeasurement();
        final GroundStation   station     = measurement.getStation();
        final SpacecraftState state       = estimated.getStates()[0];

        RangeModifierUtil.modify(estimated, getIonoModel(),
                                 new ModifierGradientConverter(state, 6, new FrameAlignedProvider(state.getFrame())),
                                 station,
                                 this::rangeErrorIonosphericModel,
                                 this::rangeErrorIonosphericModel,
                                 this);

    }

}