DSSTPropagatorBuilder.java
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package org.orekit.propagation.conversion;
import org.orekit.attitudes.Attitude;
import org.orekit.attitudes.AttitudeProvider;
import org.orekit.attitudes.FrameAlignedProvider;
import org.orekit.estimation.leastsquares.DSSTBatchLSModel;
import org.orekit.estimation.leastsquares.ModelObserver;
import org.orekit.estimation.measurements.ObservedMeasurement;
import org.orekit.orbits.EquinoctialOrbit;
import org.orekit.orbits.Orbit;
import org.orekit.orbits.OrbitType;
import org.orekit.orbits.PositionAngleType;
import org.orekit.propagation.PropagationType;
import org.orekit.propagation.Propagator;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.integration.AdditionalDerivativesProvider;
import org.orekit.propagation.semianalytical.dsst.DSSTPropagator;
import org.orekit.propagation.semianalytical.dsst.forces.DSSTForceModel;
import org.orekit.propagation.semianalytical.dsst.forces.DSSTNewtonianAttraction;
import org.orekit.utils.ParameterDriver;
import org.orekit.utils.ParameterDriversList;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/** Builder for DSST propagator.
* @author Bryan Cazabonne
* @since 10.0
*/
public class DSSTPropagatorBuilder extends AbstractPropagatorBuilder {
/** First order integrator builder for propagation. */
private final ODEIntegratorBuilder builder;
/** Force models used during the extrapolation of the orbit. */
private final List<DSSTForceModel> forceModels;
/** Type of the orbit used for the propagation.*/
private PropagationType propagationType;
/** Type of the elements used to define the orbital state.*/
private PropagationType stateType;
/** Build a new instance.
* <p>
* The reference orbit is used as a model to {@link
* #createInitialOrbit() create initial orbit}. It defines the
* inertial frame, the central attraction coefficient, and is also used together
* with the {@code positionScale} to convert from the {@link
* ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
* callers of this builder to the real orbital parameters.
* The default attitude provider is aligned with the orbit's inertial frame.
* </p>
*
* @param referenceOrbit reference orbit from which real orbits will be built
* @param builder first order integrator builder
* @param positionScale scaling factor used for orbital parameters normalization
* (typically set to the expected standard deviation of the position)
* @param propagationType type of the orbit used for the propagation (mean or osculating)
* @param stateType type of the elements used to define the orbital state (mean or osculating)
* @see #DSSTPropagatorBuilder(Orbit, ODEIntegratorBuilder, double, PropagationType,
* PropagationType, AttitudeProvider)
*/
public DSSTPropagatorBuilder(final Orbit referenceOrbit,
final ODEIntegratorBuilder builder,
final double positionScale,
final PropagationType propagationType,
final PropagationType stateType) {
this(referenceOrbit, builder, positionScale, propagationType, stateType,
FrameAlignedProvider.of(referenceOrbit.getFrame()));
}
/** Build a new instance.
* <p>
* The reference orbit is used as a model to {@link
* #createInitialOrbit() create initial orbit}. It defines the
* inertial frame, the central attraction coefficient, and is also used together
* with the {@code positionScale} to convert from the {@link
* ParameterDriver#setNormalizedValue(double) normalized} parameters used by the
* callers of this builder to the real orbital parameters.
* </p>
* @param referenceOrbit reference orbit from which real orbits will be built
* @param builder first order integrator builder
* @param positionScale scaling factor used for orbital parameters normalization
* (typically set to the expected standard deviation of the position)
* @param propagationType type of the orbit used for the propagation (mean or osculating)
* @param stateType type of the elements used to define the orbital state (mean or osculating)
* @param attitudeProvider attitude law.
* @since 10.1
*/
public DSSTPropagatorBuilder(final Orbit referenceOrbit,
final ODEIntegratorBuilder builder,
final double positionScale,
final PropagationType propagationType,
final PropagationType stateType,
final AttitudeProvider attitudeProvider) {
super(referenceOrbit, PositionAngleType.MEAN, positionScale, true, attitudeProvider, Propagator.DEFAULT_MASS);
this.builder = builder;
this.forceModels = new ArrayList<>();
this.propagationType = propagationType;
this.stateType = stateType;
}
/** Get the type of the orbit used for the propagation (mean or osculating).
* @return the type of the orbit used for the propagation
*/
public PropagationType getPropagationType() {
return propagationType;
}
/** Get the type of the elements used to define the orbital state (mean or osculating).
* @return the type of the elements used to define the orbital state
*/
public PropagationType getStateType() {
return stateType;
}
/** Get the integrator builder.
* @return the integrator builder
*/
public ODEIntegratorBuilder getIntegratorBuilder()
{
return builder;
}
/** Get the list of all force models.
* @return the list of all force models
*/
public List<DSSTForceModel> getAllForceModels()
{
return Collections.unmodifiableList(forceModels);
}
/** Add a force model to the global perturbation model.
* <p>If this method is not called at all, the integrated orbit will follow
* a Keplerian evolution only.</p>
* @param model perturbing {@link DSSTForceModel} to add
*/
public void addForceModel(final DSSTForceModel model) {
if (model instanceof DSSTNewtonianAttraction) {
// we want to add the central attraction force model
if (hasNewtonianAttraction()) {
// there is already a central attraction model, replace it
forceModels.set(forceModels.size() - 1, model);
} else {
// there are no central attraction model yet, add it at the end of the list
forceModels.add(model);
}
} else {
// we want to add a perturbing force model
if (hasNewtonianAttraction()) {
// insert the new force model before Newtonian attraction,
// which should always be the last one in the list
forceModels.add(forceModels.size() - 1, model);
} else {
// we only have perturbing force models up to now, just append at the end of the list
forceModels.add(model);
}
}
addSupportedParameters(model.getParametersDrivers());
}
/** Reset the orbit in the propagator builder.
* @param newOrbit newOrbit New orbit to set in the propagator builder
* @param orbitType orbit type (MEAN or OSCULATING)
*/
public void resetOrbit(final Orbit newOrbit, final PropagationType orbitType) {
this.stateType = orbitType;
super.resetOrbit(newOrbit);
}
/** {@inheritDoc} */
public DSSTPropagator buildPropagator(final double[] normalizedParameters) {
setParameters(normalizedParameters);
final EquinoctialOrbit orbit = (EquinoctialOrbit) OrbitType.EQUINOCTIAL.convertType(createInitialOrbit());
final Attitude attitude = getAttitudeProvider().getAttitude(orbit, orbit.getDate(), getFrame());
final SpacecraftState state = new SpacecraftState(orbit, attitude, getMass());
final DSSTPropagator propagator = new DSSTPropagator(
builder.buildIntegrator(orbit, OrbitType.EQUINOCTIAL, PositionAngleType.MEAN),
propagationType,
getAttitudeProvider());
// Configure force models
if (!hasNewtonianAttraction()) {
// There are no central attraction model yet, add it at the end of the list
addForceModel(new DSSTNewtonianAttraction(orbit.getMu()));
}
for (DSSTForceModel model : forceModels) {
propagator.addForceModel(model);
}
propagator.setInitialState(state, stateType);
// Add additional derivatives providers to the propagator
for (AdditionalDerivativesProvider provider: getAdditionalDerivativesProviders()) {
propagator.addAdditionalDerivativesProvider(provider);
}
return propagator;
}
/** {@inheritDoc} */
@Override
public DSSTBatchLSModel buildLeastSquaresModel(final PropagatorBuilder[] builders,
final List<ObservedMeasurement<?>> measurements,
final ParameterDriversList estimatedMeasurementsParameters,
final ModelObserver observer) {
return new DSSTBatchLSModel(builders,
measurements,
estimatedMeasurementsParameters,
observer,
propagationType);
}
/** Check if Newtonian attraction force model is available.
* <p>
* Newtonian attraction is always the last force model in the list.
* </p>
* @return true if Newtonian attraction force model is available
*/
private boolean hasNewtonianAttraction() {
final int last = forceModels.size() - 1;
return last >= 0 && forceModels.get(last) instanceof DSSTNewtonianAttraction;
}
}