Maneuver.java
/* Copyright 2002-2020 CS GROUP
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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
* (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
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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 java.util.Arrays;
import java.util.stream.Stream;
import org.hipparchus.Field;
import org.hipparchus.RealFieldElement;
import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.orekit.attitudes.Attitude;
import org.orekit.attitudes.AttitudeProvider;
import org.orekit.attitudes.FieldAttitude;
import org.orekit.forces.AbstractForceModel;
import org.orekit.forces.maneuvers.propulsion.PropulsionModel;
import org.orekit.forces.maneuvers.trigger.ManeuverTriggers;
import org.orekit.propagation.FieldSpacecraftState;
import org.orekit.propagation.SpacecraftState;
import org.orekit.propagation.events.EventDetector;
import org.orekit.propagation.events.FieldEventDetector;
import org.orekit.propagation.numerical.FieldTimeDerivativesEquations;
import org.orekit.propagation.numerical.TimeDerivativesEquations;
import org.orekit.time.AbsoluteDate;
import org.orekit.utils.ParameterDriver;
/** A generic model for maneuvers.
* It contains:
* - An attitude override, this is the attitude used during the maneuver, it can be different than the one
* used for propagation;
* - A maneuver triggers object from the trigger sub-package. It defines the triggers used to start and stop the maneuvers (dates or events for example).
* - A propulsion model from sub-package propulsion. It defines the thrust or ΔV, isp, flow rate etc..
* Both the propulsion model and the maneuver triggers can contain parameter drivers (for estimation).
* The convention here is that the propulsion model drivers are given before the maneuver triggers when calling the
* method {@link #getParametersDrivers()}
* @author Maxime Journot
* @since 10.2
*/
public class Maneuver extends AbstractForceModel {
/** The attitude to override during the maneuver, if set. */
private final AttitudeProvider attitudeOverride;
/** Propulsion model to use for the thrust. */
private final PropulsionModel propulsionModel;
/** Maneuver triggers. */
private final ManeuverTriggers maneuverTriggers;
/** Generic maneuver constructor.
* @param attitudeOverride attitude provider for the attitude during the maneuver
* @param maneuverTriggers maneuver triggers
* @param propulsionModel propulsion model
*/
public Maneuver(final AttitudeProvider attitudeOverride,
final ManeuverTriggers maneuverTriggers,
final PropulsionModel propulsionModel) {
this.maneuverTriggers = maneuverTriggers;
this.attitudeOverride = attitudeOverride;
this.propulsionModel = propulsionModel;
}
/** Get the name of the maneuver.
* The name can be in the propulsion model, in the maneuver triggers or both.
* If it is in both it should be the same since it refers to the same maneuver.
* The name is inferred from the propulsion model first, then from the maneuver triggers if
* the propulsion model had an empty name.
* @return the name
*/
public String getName() {
//FIXME: Potentially, throw an exception if both propulsion model
// and maneuver triggers define a name but they are different
String name = propulsionModel.getName();
if (name.length() < 1) {
name = maneuverTriggers.getName();
}
return name;
}
/** Get the attitude override used for the maneuver.
* @return the attitude override
*/
public AttitudeProvider getAttitudeOverride() {
return attitudeOverride;
}
/** Get the propulsion model.
* @return the propulsion model
*/
public PropulsionModel getPropulsionModel() {
return propulsionModel;
}
/** Get the maneuver triggers.
* @return the maneuver triggers
*/
public ManeuverTriggers getManeuverTriggers() {
return maneuverTriggers;
}
/** {@inheritDoc} */
@Override
public boolean dependsOnPositionOnly() {
return false;
}
/** {@inheritDoc} */
@Override
public void init(final SpacecraftState initialState, final AbsoluteDate target) {
propulsionModel.init(initialState, target);
maneuverTriggers.init(initialState, target);
}
/** {@inheritDoc} */
@Override
public void addContribution(final SpacecraftState s, final TimeDerivativesEquations adder) {
// Get the parameters associated to the maneuver (from ForceModel)
final double[] parameters = getParameters();
// If the maneuver is active, compute and add its contribution
// Maneuver triggers are used to check if the maneuver is currently firing or not
// Specific drivers for the triggers are extracted from the array given by the ForceModel interface
if (maneuverTriggers.isFiring(s.getDate(), getManeuverTriggersParameters(parameters))) {
// Compute thrust acceleration in inertial frame
adder.addNonKeplerianAcceleration(acceleration(s, parameters));
// Compute flow rate using the propulsion model
// Specific drivers for the propulsion model are extracted from the array given by the ForceModel interface
adder.addMassDerivative(propulsionModel.getMassDerivatives(s, getPropulsionModelParameters(parameters)));
}
}
/** {@inheritDoc} */
@Override
public <T extends RealFieldElement<T>> void addContribution(final FieldSpacecraftState<T> s,
final FieldTimeDerivativesEquations<T> adder) {
// Get the parameters associated to the maneuver (from ForceModel)
final T[] parameters = getParameters(s.getDate().getField());
// If the maneuver is active, compute and add its contribution
// Maneuver triggers are used to check if the maneuver is currently firing or not
// Specific drivers for the triggers are extracted from the array given by the ForceModel interface
if (maneuverTriggers.isFiring(s.getDate(), getManeuverTriggersParameters(parameters))) {
// Compute thrust acceleration in inertial frame
adder.addNonKeplerianAcceleration(acceleration(s, parameters));
// Compute flow rate using the propulsion model
// Specific drivers for the propulsion model are extracted from the array given by the ForceModel interface
adder.addMassDerivative(propulsionModel.getMassDerivatives(s, getPropulsionModelParameters(parameters)));
}
}
@Override
public Vector3D acceleration(final SpacecraftState s, final double[] parameters) {
// If the maneuver is active, compute and add its contribution
// Maneuver triggers are used to check if the maneuver is currently firing or not
// Specific drivers for the triggers are extracted from the array given by the ForceModel interface
if (maneuverTriggers.isFiring(s.getDate(), getManeuverTriggersParameters(parameters))) {
// Attitude during maneuver
final Attitude maneuverAttitude =
attitudeOverride == null ?
s.getAttitude() :
attitudeOverride.getAttitude(s.getOrbit(),
s.getDate(),
s.getFrame());
// Compute acceleration from propulsion model
// Specific drivers for the propulsion model are extracted from the array given by the ForceModel interface
return propulsionModel.getAcceleration(s, maneuverAttitude, getPropulsionModelParameters(parameters));
} else {
// Constant (and null) acceleration when not firing
return Vector3D.ZERO;
}
}
@Override
public <T extends RealFieldElement<T>> FieldVector3D<T> acceleration(final FieldSpacecraftState<T> s, final T[] parameters) {
// If the maneuver is active, compute and add its contribution
// Maneuver triggers are used to check if the maneuver is currently firing or not
// Specific drivers for the triggers are extracted from the array given by the ForceModel interface
if (maneuverTriggers.isFiring(s.getDate(), getManeuverTriggersParameters(parameters))) {
// Attitude during maneuver
final FieldAttitude<T> maneuverAttitude =
attitudeOverride == null ?
s.getAttitude() :
attitudeOverride.getAttitude(s.getOrbit(),
s.getDate(),
s.getFrame());
// Compute acceleration from propulsion model
// Specific drivers for the propulsion model are extracted from the array given by the ForceModel interface
return propulsionModel.getAcceleration(s, maneuverAttitude, getPropulsionModelParameters(parameters));
} else {
// Constant (and null) acceleration when not firing
return FieldVector3D.getZero(s.getMu().getField());
}
}
/** {@inheritDoc} */
@Override
public Stream<EventDetector> getEventsDetectors() {
// Event detectors are extracted from the maneuver triggers
return maneuverTriggers.getEventsDetectors();
}
/** {@inheritDoc} */
@Override
public <T extends RealFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventsDetectors(final Field<T> field) {
// Event detectors are extracted from the maneuver triggers
return maneuverTriggers.getFieldEventsDetectors(field);
}
@Override
public ParameterDriver[] getParametersDrivers() {
// Extract parameter drivers from propulsion model and maneuver triggers
final ParameterDriver[] propulsionModelDrivers = propulsionModel.getParametersDrivers();
final ParameterDriver[] maneuverTriggersDrivers = maneuverTriggers.getParametersDrivers();
final int propulsionModelDriversLength = propulsionModelDrivers.length;
final int maneuverTriggersDriversLength = maneuverTriggersDrivers.length;
// Prepare final drivers' array
final ParameterDriver[] drivers = new ParameterDriver[propulsionModelDriversLength + maneuverTriggersDriversLength];
// Convention: Propulsion drivers are given before maneuver triggers drivers
// Add propulsion drivers first
System.arraycopy(propulsionModelDrivers, 0, drivers, 0, propulsionModelDriversLength);
// Then maneuver triggers' drivers
System.arraycopy(maneuverTriggersDrivers, 0, drivers, propulsionModelDriversLength, maneuverTriggersDriversLength);
// Return full drivers' array
return drivers;
}
/** Extract propulsion model parameters from the parameters' array called in by the ForceModel interface.
* Convention: Propulsion parameters are given before maneuver triggers parameters
* @param parameters parameters' array called in by ForceModel interface
* @return propulsion model parameters
*/
private double[] getPropulsionModelParameters(final double[] parameters) {
return Arrays.copyOfRange(parameters, 0, propulsionModel.getParametersDrivers().length);
}
/** Extract propulsion model parameters from the parameters' array called in by the ForceModel interface.
* Convention: Propulsion parameters are given before maneuver triggers parameters
* @param parameters parameters' array called in by ForceModel interface
* @param <T> extends RealFieldElement<T>
* @return propulsion model parameters
*/
private <T extends RealFieldElement<T>> T[] getPropulsionModelParameters(final T[] parameters) {
return Arrays.copyOfRange(parameters, 0, propulsionModel.getParametersDrivers().length);
}
/** Extract maneuver triggers' parameters from the parameters' array called in by the ForceModel interface.
* Convention: Propulsion parameters are given before maneuver triggers parameters
* @param parameters parameters' array called in by ForceModel interface
* @return maneuver triggers' parameters
*/
private double[] getManeuverTriggersParameters(final double[] parameters) {
final int nbPropulsionModelDrivers = propulsionModel.getParametersDrivers().length;
return Arrays.copyOfRange(parameters, nbPropulsionModelDrivers,
nbPropulsionModelDrivers + maneuverTriggers.getParametersDrivers().length);
}
/** Extract maneuver triggers' parameters from the parameters' array called in by the ForceModel interface.
* Convention: Propulsion parameters are given before maneuver triggers parameters
* @param parameters parameters' array called in by ForceModel interface
* @param <T> extends RealFieldElement<T>
* @return maneuver triggers' parameters
*/
private <T extends RealFieldElement<T>> T[] getManeuverTriggersParameters(final T[] parameters) {
final int nbPropulsionModelDrivers = propulsionModel.getParametersDrivers().length;
return Arrays.copyOfRange(parameters, nbPropulsionModelDrivers,
nbPropulsionModelDrivers + maneuverTriggers.getParametersDrivers().length);
}
}