BrouwerLyddaneOrbitalState.java
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*
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package org.orekit.propagation.conversion.averaging;
import org.orekit.forces.gravity.potential.UnnormalizedSphericalHarmonicsProvider;
import org.orekit.frames.Frame;
import org.orekit.orbits.KeplerianOrbit;
import org.orekit.orbits.Orbit;
import org.orekit.orbits.OrbitType;
import org.orekit.orbits.PositionAngleType;
import org.orekit.propagation.PropagationType;
import org.orekit.propagation.analytical.BrouwerLyddanePropagator;
import org.orekit.time.AbsoluteDate;
import org.orekit.propagation.conversion.averaging.elements.AveragedKeplerianWithMeanAngle;
/**
* Class representing an averaged orbital state as in the Brouwer-Lyddane theory.
*
* @author Romain Serra
* @see AveragedOrbitalState
* @see BrouwerLyddanePropagator
* @since 12.1
*/
public class BrouwerLyddaneOrbitalState extends AbstractHarmonicsBasedOrbitalState {
/** So-called M2 coefficient, set to zero. */
private static final double M2 = 0.;
/** Averaged Keplerian elements. */
private final AveragedKeplerianWithMeanAngle averagedElements;
/**
* Constructor.
* @param date epoch
* @param elements averaged orbital elements
* @param frame reference frame
* @param harmonicsProvider spherical harmonics provider
*/
public BrouwerLyddaneOrbitalState(final AbsoluteDate date,
final AveragedKeplerianWithMeanAngle elements,
final Frame frame,
final UnnormalizedSphericalHarmonicsProvider harmonicsProvider) {
super(date, frame, harmonicsProvider);
this.averagedElements = elements;
}
/** {@inheritDoc} */
@Override
public OrbitType getOrbitType() {
return OrbitType.KEPLERIAN;
}
/** {@inheritDoc} */
@Override
public PositionAngleType getPositionAngleType() {
return PositionAngleType.MEAN;
}
/** {@inheritDoc} */
@Override
public AveragedKeplerianWithMeanAngle getAveragedElements() {
return averagedElements;
}
/** {@inheritDoc} */
@Override
public Orbit toOsculatingOrbit() {
final BrouwerLyddanePropagator propagator = createPropagator();
return propagator.propagateOrbit(getDate());
}
/**
* Create Brouwer-Lyddane propagator.
* @return propagator using relevant theory
*/
private BrouwerLyddanePropagator createPropagator() {
final KeplerianOrbit orekitOrbit = createOrekitOrbit();
return new BrouwerLyddanePropagator(orekitOrbit, getHarmonicsProvider(),
PropagationType.MEAN, M2);
}
/**
* Create Keplerian orbit representation of averaged state.
* @return Keplerian orbit
*/
private KeplerianOrbit createOrekitOrbit() {
return new KeplerianOrbit(averagedElements.getAveragedSemiMajorAxis(),
averagedElements.getAveragedEccentricity(), averagedElements.getAveragedInclination(),
averagedElements.getAveragedPerigeeArgument(),
averagedElements.getAveragedRightAscensionOfTheAscendingNode(),
averagedElements.getAveragedMeanAnomaly(), getPositionAngleType(), getFrame(),
getDate(), getMu());
}
}