ITRFProvider.java
/* Copyright 2002-2024 CS GROUP
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* 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
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package org.orekit.frames;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.geometry.euclidean.threed.FieldRotation;
import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
import org.hipparchus.geometry.euclidean.threed.Rotation;
import org.hipparchus.geometry.euclidean.threed.RotationConvention;
import org.hipparchus.geometry.euclidean.threed.RotationOrder;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.utils.Constants;
/** International Terrestrial Reference Frame.
* <p> Handles pole motion effects and depends on {@link TIRFProvider}, its
* parent frame.</p>
* @author Luc Maisonobe
*/
class ITRFProvider implements EOPBasedTransformProvider {
/** Serializable UID. */
private static final long serialVersionUID = 20130922L;
/** S' rate in radians per julian century.
* Approximately -47 microarcsecond per julian century (Lambert and Bizouard, 2002)
*/
private static final double S_PRIME_RATE = -47e-6 * Constants.ARC_SECONDS_TO_RADIANS;
/** EOP history. */
private final EOPHistory eopHistory;
/** Simple constructor.
* @param eopHistory EOP history
*/
ITRFProvider(final EOPHistory eopHistory) {
this.eopHistory = eopHistory;
}
/** {@inheritDoc} */
@Override
public EOPHistory getEOPHistory() {
return eopHistory;
}
/** {@inheritDoc} */
@Override
public ITRFProvider getNonInterpolatingProvider() {
return new ITRFProvider(eopHistory.getEOPHistoryWithoutCachedTidalCorrection());
}
/** {@inheritDoc} */
@Override
public Transform getTransform(final AbsoluteDate date) {
// offset from J2000 epoch in Julian centuries
final double tts = date.durationFrom(eopHistory.getTimeScales().getJ2000Epoch());
final double ttc = tts / Constants.JULIAN_CENTURY;
// pole correction parameters
final PoleCorrection eop = eopHistory.getPoleCorrection(date);
// pole motion in terrestrial frame
final Rotation wRot = new Rotation(RotationOrder.XYZ, RotationConvention.FRAME_TRANSFORM,
eop.getYp(), eop.getXp(), -S_PRIME_RATE * ttc);
// combined effects
final Rotation combined = wRot.revert();
// set up the transform from parent TIRF
return new Transform(date, combined, Vector3D.ZERO);
}
/** {@inheritDoc} */
@Override
public <T extends CalculusFieldElement<T>> FieldTransform<T> getTransform(final FieldAbsoluteDate<T> date) {
// offset from J2000 epoch in Julian centuries
final T tts = date.durationFrom(eopHistory.getTimeScales().getJ2000Epoch());
final T ttc = tts.divide(Constants.JULIAN_CENTURY);
// pole correction parameters
final FieldPoleCorrection<T> eop = eopHistory.getPoleCorrection(date);
// pole motion in terrestrial frame
final FieldRotation<T> wRot = new FieldRotation<>(RotationOrder.XYZ, RotationConvention.FRAME_TRANSFORM,
eop.getYp(),
eop.getXp(),
ttc.multiply(-S_PRIME_RATE));
// combined effects
final FieldRotation<T> combined = wRot.revert();
// set up the transform from parent TIRF
return new FieldTransform<>(date, combined, FieldVector3D.getZero(date.getField()));
}
}