Apm.java
/* Copyright 2002-2022 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
*
* 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.files.ccsds.ndm.adm.apm;
import java.util.List;
import org.hipparchus.complex.Quaternion;
import org.orekit.attitudes.Attitude;
import org.orekit.data.DataContext;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.files.ccsds.ndm.NdmConstituent;
import org.orekit.files.ccsds.ndm.adm.AdmMetadata;
import org.orekit.files.ccsds.ndm.adm.AttitudeType;
import org.orekit.files.ccsds.section.Header;
import org.orekit.files.ccsds.section.Segment;
import org.orekit.frames.Frame;
import org.orekit.utils.IERSConventions;
import org.orekit.utils.PVCoordinatesProvider;
import org.orekit.utils.TimeStampedAngularCoordinates;
/**
* This class stores all the information of the Attitude Parameter Message (APM) File parsed
* by APMParser. It contains the header and the metadata and a the data lines.
* @author Bryan Cazabonne
* @since 10.2
*/
public class Apm extends NdmConstituent<Header, Segment<AdmMetadata, ApmData>> {
/** Root element for XML files. */
public static final String ROOT = "apm";
/** Key for format version. */
public static final String FORMAT_VERSION_KEY = "CCSDS_APM_VERS";
/** Simple constructor.
* @param header file header
* @param segments file segments
* @param conventions IERS conventions
* @param dataContext used for creating frames, time scales, etc.
*/
public Apm(final Header header, final List<Segment<AdmMetadata, ApmData>> segments,
final IERSConventions conventions, final DataContext dataContext) {
super(header, segments, conventions, dataContext);
}
/** Get the file metadata.
* @return file metadata
*/
public AdmMetadata getMetadata() {
return getSegments().get(0).getMetadata();
}
/** Get the file data.
* @return file data
*/
public ApmData getData() {
return getSegments().get(0).getData();
}
/** Get the attitude.
* <p>
* The orientation part of the attitude is always extracted from the file mandatory
* {@link ApmQuaternion quaternion logical block}. The rotation rate part of
* the attitude is extracted from the {@link ApmQuaternion quaternion logical block}
* if rate is available there, or from the {@link Euler Euler logical block} if rate
* is missing from quaternion logical block but available in Euler logical block.
* </p>
* @param frame reference frame with respect to which attitude must be defined,
* (may be null if attitude is <em>not</em> orbit-relative and one wants
* attitude in the same frame as used in the attitude message)
* @param pvProvider provider for spacecraft position and velocity
* (may be null if attitude is <em>not</em> orbit-relative)
* @return attitude
*/
public Attitude getAttitude(final Frame frame, final PVCoordinatesProvider pvProvider) {
final ApmData data = getSegments().get(0).getData();
final ApmQuaternion qBlock = data.getQuaternionBlock();
final Euler eBlock = data.getEulerBlock();
final TimeStampedAngularCoordinates tac;
if (qBlock.hasRates()) {
// quaternion logical block includes everything we need
final Quaternion q = qBlock.getQuaternion();
final Quaternion qDot = qBlock.getQuaternionDot();
tac = AttitudeType.QUATERNION_DERIVATIVE.build(true, qBlock.getEndpoints().isExternal2SpacecraftBody(),
null, true, qBlock.getEpoch(),
q.getQ0(), q.getQ1(), q.getQ2(), q.getQ3(),
qDot.getQ0(), qDot.getQ1(), qDot.getQ2(), qDot.getQ3());
} else if (eBlock != null && eBlock.hasRates()) {
// we have to rely on the Euler logical block to take rates into account
if (!qBlock.getEndpoints().isCompatibleWith(eBlock.getEndpoints())) {
// nothing really prevents having two logical blocks with different settings
// but it is a nightmare to process and probably not worse the trouble.
// For now, we just throw an exception, we may reconsider this if some use case arises
throw new OrekitException(OrekitMessages.INCOMPATIBLE_FRAMES,
qBlock.getEndpoints().toString(),
eBlock.getEndpoints().toString());
}
final Quaternion q = qBlock.getQuaternion();
final double[] rates = eBlock.getRotationRates();
tac = AttitudeType.QUATERNION_RATE.build(true,
qBlock.getEndpoints().isExternal2SpacecraftBody(),
eBlock.getEulerRotSeq(), eBlock.isSpacecraftBodyRate(), qBlock.getEpoch(),
q.getQ0(), q.getQ1(), q.getQ2(), q.getQ3(),
rates[0], rates[1], rates[2]);
} else {
// we rely only on the quaternion logical block, despite it doesn't include rates
final Quaternion q = qBlock.getQuaternion();
tac = AttitudeType.QUATERNION.build(true, qBlock.getEndpoints().isExternal2SpacecraftBody(),
null, true, qBlock.getEpoch(),
q.getQ0(), q.getQ1(), q.getQ2(), q.getQ3());
}
// build the attitude
return qBlock.getEndpoints().build(frame, pvProvider, tac);
}
}