CartesianCovariance.java
/* Copyright 2002-2026 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
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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
* distributed under the License is distributed on an "AS IS" BASIS,
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package org.orekit.files.ccsds.ndm.odm;
import java.util.function.Supplier;
import org.hipparchus.linear.MatrixUtils;
import org.hipparchus.linear.RealMatrix;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.files.ccsds.definitions.CcsdsFrameMapper;
import org.orekit.files.ccsds.definitions.FrameFacade;
import org.orekit.files.ccsds.section.CommentsContainer;
import org.orekit.files.ccsds.section.Data;
import org.orekit.frames.Frame;
import org.orekit.time.AbsoluteDate;
/** Container for OPM/OMM/OCM Cartesian covariance matrix.
* <p>
* Beware that the Orekit getters and setters all rely on SI units. The parsers
* and writers take care of converting these SI units into CCSDS mandatory units.
* The {@link org.orekit.utils.units.Unit Unit} class provides useful
* {@link org.orekit.utils.units.Unit#fromSI(double) fromSi} and
* {@link org.orekit.utils.units.Unit#toSI(double) toSI} methods in case the callers
* already use CCSDS units instead of the API SI units. The general-purpose
* {@link org.orekit.utils.units.Unit Unit} class (without an 's') and the
* CCSDS-specific {@link org.orekit.files.ccsds.definitions.Units Units} class
* (with an 's') also provide some predefined units. These predefined units and the
* {@link org.orekit.utils.units.Unit#fromSI(double) fromSi} and
* {@link org.orekit.utils.units.Unit#toSI(double) toSI} conversion methods are indeed
* what the parsers and writers use for the conversions.
* </p>
* @author sports
* @since 6.1
*/
public class CartesianCovariance extends CommentsContainer implements Data {
/** Labels for matrix row/columns. */
private static final String[] LABELS = {
"X", "Y", "Z", "X_DOT", "Y_DOT", "Z_DOT"
};
/** Supplier for default reference frame. */
private final Supplier<FrameFacade> defaultFrameSupplier;
/** For creating a {@link Frame}. */
private final CcsdsFrameMapper frameMapper;
/** Matrix epoch. */
private AbsoluteDate epoch;
/** Reference frame in which data are given. */
private FrameFacade referenceFrame;
/** Position/Velocity covariance matrix. */
private final RealMatrix covarianceMatrix;
/**
* Create an empty data set.
*
* @param defaultFrameSupplier supplier for default reference frame if no
* frame is specified in the CCSDS message
* @param frameMapper for creating a {@link Frame}.
* @since 14.0
*/
public CartesianCovariance(final Supplier<FrameFacade> defaultFrameSupplier,
final CcsdsFrameMapper frameMapper) {
this.defaultFrameSupplier = defaultFrameSupplier;
this.frameMapper = frameMapper;
covarianceMatrix = MatrixUtils.createRealMatrix(6, 6);
for (int i = 0; i < covarianceMatrix.getRowDimension(); ++i) {
for (int j = 0; j <= i; ++j) {
covarianceMatrix.setEntry(i, j, Double.NaN);
}
}
}
/** {@inheritDoc} */
@Override
public void validate(final double version) {
super.validate(version);
checkNotNull(epoch, CartesianCovarianceKey.EPOCH.name());
for (int i = 0; i < covarianceMatrix.getRowDimension(); ++i) {
for (int j = 0; j <= i; ++j) {
if (Double.isNaN(covarianceMatrix.getEntry(i, j))) {
throw new OrekitException(OrekitMessages.CCSDS_MISSING_KEYWORD,
"C" + LABELS[i] + "_" + LABELS[j]);
}
}
}
}
/** Get matrix epoch.
* @return matrix epoch
*/
public AbsoluteDate getEpoch() {
return epoch;
}
/** Set matrix epoch.
* @param epoch matrix epoch
*/
public void setEpoch(final AbsoluteDate epoch) {
refuseFurtherComments();
this.epoch = epoch;
}
/**
* Get the reference frame.
*
* @return The reference frame specified by the {@code COV_REF_FRAME} keyword
* or inherited from metadata
*/
public FrameFacade getReferenceFrame() {
return referenceFrame == null ? defaultFrameSupplier.get() : referenceFrame;
}
/** Set the reference frame in which data are given.
* @param referenceFrame the reference frame to be set
*/
public void setReferenceFrame(final FrameFacade referenceFrame) {
refuseFurtherComments();
this.referenceFrame = referenceFrame;
}
/**
* Get the mapping between a CCSDS frame and a {@link Frame}.
*
* @return the frame mapper.
* @since 14.0
*/
public CcsdsFrameMapper getFrameMapper() {
return frameMapper;
}
/**
* Get the frame in which this covariance matrix is defined. Note that only
* the orientation of the returned frame is significant, the position of the
* returned frame is irrelevant and should be ignored.
*
* @return Orekit frame for this covariance matrix.
* @see #getReferenceFrame()
* @see #getFrameMapper()
* @since 14.0
*/
public Frame getFrame() {
// OEM, OMM, and OPM don't allow a COV_FRAME_EPOCH, but OCM does.
// This class is not used for OCM, which allows non-Cartesian covariance
return getFrameMapper().buildCcsdsFrame(getReferenceFrame(), null);
}
/** Get the Position/Velocity covariance matrix.
* @return the Position/Velocity covariance matrix
*/
public RealMatrix getCovarianceMatrix() {
return covarianceMatrix;
}
/** Set an entry in the Position/Velocity covariance matrix.
* <p>
* Both m(j, k) and m(k, j) are set.
* </p>
* @param j row index (must be between 0 and 5 (inclusive)
* @param k column index (must be between 0 and 5 (inclusive)
* @param entry value of the matrix entry
*/
public void setCovarianceMatrixEntry(final int j, final int k, final double entry) {
refuseFurtherComments();
covarianceMatrix.setEntry(j, k, entry);
covarianceMatrix.setEntry(k, j, entry);
}
}