FieldImpulseManeuver.java
/* Copyright 2020-2023 Exotrail
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* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
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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
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package org.orekit.forces.maneuvers;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.geometry.euclidean.threed.FieldRotation;
import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
import org.hipparchus.ode.events.Action;
import org.hipparchus.util.FastMath;
import org.orekit.attitudes.AttitudeProvider;
import org.orekit.orbits.FieldCartesianOrbit;
import org.orekit.propagation.FieldSpacecraftState;
import org.orekit.propagation.events.FieldAbstractDetector;
import org.orekit.propagation.events.FieldAdaptableInterval;
import org.orekit.propagation.events.FieldEventDetector;
import org.orekit.propagation.events.handlers.FieldEventHandler;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.utils.Constants;
import org.orekit.utils.FieldArrayDictionary;
import org.orekit.utils.FieldPVCoordinates;
/** Impulse maneuver model for propagators working with Fields.
* <p>This class implements an impulse maneuver as a discrete event
* that can be provided to any {@link org.orekit.propagation.FieldPropagator
* Propagator} and mirrors the standard version
* {@link org.orekit.forces.maneuvers.ImpulseManeuver}.</p>
* <p>The maneuver is triggered when an underlying event generates a
* {@link Action#STOP STOP} event, in which case this class will generate a {@link
* Action#RESET_STATE RESET_STATE}
* event (the stop event from the underlying object is therefore filtered out).
* In the simple cases, the underlying event detector may be a basic
* {@link org.orekit.propagation.events.FieldDateDetector date event}, but it
* can also be a more elaborate {@link
* org.orekit.propagation.events.FieldApsideDetector apside event} for apogee
* maneuvers for example.</p>
* <p>The maneuver is defined by a single velocity increment.
* If no AttitudeProvider is given, the current attitude of the spacecraft,
* defined by the current spacecraft state, will be used as the
* {@link AttitudeProvider} so the velocity increment should be given in
* the same pseudoinertial frame as the {@link FieldSpacecraftState} used to
* construct the propagator that will handle the maneuver.
* If an AttitudeProvider is given, the velocity increment given should be
* defined appropriately in consideration of that provider. So, a typical
* case for tangential maneuvers is to provide a {@link org.orekit.attitudes.LofOffset LOF aligned}
* attitude provider along with a velocity increment defined in accordance with
* that LOF aligned attitude provider; e.g. if the LOF aligned attitude provider
* was constructed using LOFType.VNC the velocity increment should be
* provided in VNC coordinates.</p>
* <p>The norm through which the delta-V maps to the mass consumption is chosen via the
* enum {@link Control3DVectorCostType}. Default is Euclidean. </p>
* <p>Beware that the triggering event detector must behave properly both
* before and after maneuver. If for example a node detector is used to trigger
* an inclination maneuver and the maneuver change the orbit to an equatorial one,
* the node detector will fail just after the maneuver, being unable to find a
* node on an equatorial orbit! This is a real case that has been encountered
* during validation ...</p>
* @see org.orekit.propagation.FieldPropagator#addEventDetector(FieldEventDetector)
* @see org.orekit.forces.maneuvers.ImpulseManeuver
* @author Romain Serra
* @since 12.0
* @param <D> type of the detector
* @param <T> type of the field elements
*/
public class FieldImpulseManeuver<D extends FieldEventDetector<T>, T extends CalculusFieldElement<T>>
extends FieldAbstractDetector<FieldImpulseManeuver<D, T>, T> {
/** The attitude to override during the maneuver, if set. */
private final AttitudeProvider attitudeOverride;
/** Triggering event. */
private final D trigger;
/** Velocity increment in satellite frame. */
private final FieldVector3D<T> deltaVSat;
/** Specific impulse. */
private final T isp;
/** Engine exhaust velocity. */
private final T vExhaust;
/** Indicator for forward propagation. */
private boolean forward;
/** Type of norm linking delta-V to mass consumption. */
private final Control3DVectorCostType control3DVectorCostType;
/** Build a new instance.
* @param trigger triggering event
* @param deltaVSat velocity increment in satellite frame
* @param isp engine specific impulse (s)
*/
public FieldImpulseManeuver(final D trigger, final FieldVector3D<T> deltaVSat, final T isp) {
this(trigger, null, deltaVSat, isp);
}
/** Build a new instance.
* @param trigger triggering event
* @param attitudeOverride the attitude provider to use for the maneuver
* @param deltaVSat velocity increment in satellite frame
* @param isp engine specific impulse (s)
*/
public FieldImpulseManeuver(final D trigger, final AttitudeProvider attitudeOverride,
final FieldVector3D<T> deltaVSat, final T isp) {
this(trigger.getMaxCheckInterval(), trigger.getThreshold(), trigger.getMaxIterationCount(),
new Handler<>(), trigger, attitudeOverride, deltaVSat, isp,
Control3DVectorCostType.TWO_NORM);
}
/** Build a new instance.
* @param trigger triggering event
* @param attitudeOverride the attitude provider to use for the maneuver
* @param deltaVSat velocity increment in satellite frame
* @param isp engine specific impulse (s)
* @param control3DVectorCostType increment's norm for mass consumption
*/
public FieldImpulseManeuver(final D trigger, final AttitudeProvider attitudeOverride,
final FieldVector3D<T> deltaVSat, final T isp,
final Control3DVectorCostType control3DVectorCostType) {
this(trigger.getMaxCheckInterval(), trigger.getThreshold(), trigger.getMaxIterationCount(),
new Handler<>(), trigger, attitudeOverride, deltaVSat, isp, control3DVectorCostType);
}
/** Private constructor with full parameters.
* <p>
* This constructor is private as users are expected to use the builder
* API with the various {@code withXxx()} methods to set up the instance
* in a readable manner without using a huge amount of parameters.
* </p>
* @param maxCheck maximum checking interval
* @param threshold convergence threshold (s)
* @param maxIter maximum number of iterations in the event time search
* @param eventHandler event handler to call at event occurrences
* @param trigger triggering event
* @param attitudeOverride the attitude provider to use for the maneuver
* @param deltaVSat velocity increment in satellite frame
* @param isp engine specific impulse (s)
* @param control3DVectorCostType increment's norm for mass consumption
*/
private FieldImpulseManeuver(final FieldAdaptableInterval<T> maxCheck, final T threshold, final int maxIter,
final FieldEventHandler<T> eventHandler, final D trigger,
final AttitudeProvider attitudeOverride, final FieldVector3D<T> deltaVSat,
final T isp, final Control3DVectorCostType control3DVectorCostType) {
super(maxCheck, threshold, maxIter, eventHandler);
this.trigger = trigger;
this.deltaVSat = deltaVSat;
this.isp = isp;
this.attitudeOverride = attitudeOverride;
this.control3DVectorCostType = control3DVectorCostType;
this.vExhaust = this.isp.multiply(Constants.G0_STANDARD_GRAVITY);
}
/** {@inheritDoc} */
@Override
protected FieldImpulseManeuver<D, T> create(final FieldAdaptableInterval<T> newMaxCheck, final T newThreshold,
final int newMaxIter,
final FieldEventHandler<T> fieldEventHandler) {
return new FieldImpulseManeuver<>(newMaxCheck, newThreshold, newMaxIter, fieldEventHandler,
trigger, attitudeOverride, deltaVSat, isp, control3DVectorCostType);
}
/** {@inheritDoc} */
@Override
public void init(final FieldSpacecraftState<T> s0, final FieldAbsoluteDate<T> t) {
forward = t.durationFrom(s0.getDate()).getReal() >= 0;
// Initialize the triggering event
trigger.init(s0, t);
}
/** {@inheritDoc} */
@Override
public T g(final FieldSpacecraftState<T> fieldSpacecraftState) {
return trigger.g(fieldSpacecraftState);
}
/**
* Get the Attitude Provider to use during maneuver.
* @return the attitude provider
*/
public AttitudeProvider getAttitudeOverride() {
return attitudeOverride;
}
/** Get the triggering event.
* @return triggering event
*/
public FieldEventDetector<T> getTrigger() {
return trigger;
}
/** Get the velocity increment in satellite frame.
* @return velocity increment in satellite frame
*/
public FieldVector3D<T> getDeltaVSat() {
return deltaVSat;
}
/** Get the specific impulse.
* @return specific impulse
*/
public T getIsp() {
return isp;
}
/** Get the control vector's cost type.
* @return control cost type
* @since 12.0
*/
public Control3DVectorCostType getControl3DVectorCostType() {
return control3DVectorCostType;
}
/** Local handler. */
private static class Handler<T extends CalculusFieldElement<T>> implements FieldEventHandler<T> {
/** {@inheritDoc} */
@Override
public Action eventOccurred(final FieldSpacecraftState<T> s,
final FieldEventDetector<T> detector,
final boolean increasing) {
// filter underlying event
final FieldImpulseManeuver<?, T> im = (FieldImpulseManeuver<?, T>) detector;
final Action underlyingAction = im.trigger.getHandler().eventOccurred(s, im.trigger,
increasing);
return (underlyingAction == Action.STOP) ? Action.RESET_STATE : Action.CONTINUE;
}
/** {@inheritDoc} */
@Override
public FieldSpacecraftState<T> resetState(final FieldEventDetector<T> detector,
final FieldSpacecraftState<T> oldState) {
final FieldImpulseManeuver<?, T> im = (FieldImpulseManeuver<?, T>) detector;
final FieldAbsoluteDate<T> date = oldState.getDate();
final FieldRotation<T> rotation;
if (im.getAttitudeOverride() == null) {
rotation = oldState.getAttitude().getRotation();
} else {
rotation = im.attitudeOverride.getAttitudeRotation(oldState.getOrbit(), date,
oldState.getFrame());
}
// convert velocity increment in inertial frame
final FieldVector3D<T> deltaV = rotation.applyInverseTo(im.deltaVSat);
final T one = oldState.getMu().getField().getOne();
final T sign = (im.forward) ? one : one.negate();
// apply increment to position/velocity
final FieldPVCoordinates<T> oldPV = oldState.getPVCoordinates();
final FieldPVCoordinates<T> newPV =
new FieldPVCoordinates<>(oldPV.getPosition(),
new FieldVector3D<>(one, oldPV.getVelocity(), sign, deltaV));
final FieldCartesianOrbit<T> newOrbit =
new FieldCartesianOrbit<>(newPV, oldState.getFrame(), date, oldState.getMu());
// compute new mass
final T normDeltaV = im.control3DVectorCostType.evaluate(im.deltaVSat);
final T newMass = oldState.getMass().multiply(FastMath.exp(normDeltaV.multiply(sign.negate()).divide(im.vExhaust)));
// pack everything in a new state
FieldSpacecraftState<T> newState = new FieldSpacecraftState<>(oldState.getOrbit().getType().normalize(newOrbit, oldState.getOrbit()),
oldState.getAttitude(), newMass);
for (final FieldArrayDictionary<T>.Entry entry : oldState.getAdditionalStatesValues().getData()) {
newState = newState.addAdditionalState(entry.getKey(), entry.getValue());
}
for (final FieldArrayDictionary<T>.Entry entry : oldState.getAdditionalStatesDerivatives().getData()) {
newState = newState.addAdditionalStateDerivative(entry.getKey(), entry.getValue());
}
return newState;
}
}
}