org.orekit.forces.maneuvers
Class VariableThrustManeuver

java.lang.Object
  org.orekit.parameter.Parameterizable
      org.orekit.parameter.JacobiansParameterizable
          org.orekit.forces.maneuvers.VariableThrustManeuver

All Implemented Interfaces:

Serializable, ForceModel, GradientModel, IJacobiansParameterizable, IParameterizable

public class VariableThrustManeuver
extends JacobiansParameterizable
implements ForceModel, GradientModel

This class implements a maneuver using variable thrust and ISP.

The maneuver is defined by a direction in satellite frame or in a frame defined by user or in a LOF with type defined by user. The current attitude of the spacecraft, defined by the current spacecraft state, will be used to compute the thrust direction in the inertial frame when direction is defined in satellite frame.

The maneuver is associated to two triggering EventDetector (one to start the thrust, the other one to stop the thrust): the maneuver is triggered only if the underlying event generates a STOP event, in which case this class will generate a RESET_STATE event (the stop event from the underlying object is therefore filtered out).

Since:

1.2

Version:

$Id: VariableThrustManeuver.java 16755 2016-10-07 15:47:40Z bignon $

See Also:

Serialized Form

Concurrency :

not thread-safe

Concurrency comment :

internal mutable attributes

Constructor Summary

VariableThrustManeuver(AbsoluteDate date, double duration, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName)
Constructor for a variable direction in spacecraft frame, thrust and ISP.

VariableThrustManeuver(AbsoluteDate date, double duration, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName, Frame refFrame)
Constructor for a variable direction in provided frame, thrust and ISP.

VariableThrustManeuver(AbsoluteDate date, double duration, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName, LOFType lofTyp)
Constructor for a variable direction in provided local orbital frame, thrust and ISP expressed in a LocalOrbitalFrame.

VariableThrustManeuver(EventDetector startEventDetector, EventDetector stopEventDetector, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName)
Constructor for a variable direction in spacecraft frame, thrust and ISP.

VariableThrustManeuver(EventDetector startEventDetector, EventDetector stopEventDetector, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName, Frame refFrame)
Constructor for a variable direction in provided frame, thrust and ISP.

VariableThrustManeuver(EventDetector startEventDetector, EventDetector stopEventDetector, IDependentVariable<SpacecraftState> variableThrust, IDependentVariable<SpacecraftState> variableIsp, IDependentVectorVariable<SpacecraftState> variableDirection, MassProvider massModel, String partName, LOFType lofTyp)
Constructor for a variable direction in provided local orbital frame, thrust and ISP expressed in a LocalOrbitalFrame.

Method Summary

void	addContribution(SpacecraftState s, TimeDerivativesEquations adder) Compute the contribution of the force model to the perturbing acceleration.
void	addDAccDParam(SpacecraftState s, Parameter param, double[] dAccdParam) Compute acceleration derivatives with respect to additional parameters.
void	addDAccDState(SpacecraftState s, double[][] dAccdPos, double[][] dAccdVel) Compute acceleration derivatives with respect to state parameters.
Vector3D	computeAcceleration(SpacecraftState s) Compute the acceleration due to the force.
boolean	computeGradientPosition() This method returns true if the acceleration partial derivatives with respect to position have to be computed.
boolean	computeGradientVelocity() This method returns true if the acceleration partial derivatives with respect to velocity have to be computed.
Vector3D	getDirection(SpacecraftState s) Get the thrust direction.
AbsoluteDate	getEndDate() Return the maneuver stop date (if a date or a DateDetector as been provided).
EventDetector[]	getEventsDetectors() Get the discrete events related to the model.
double	getFlowRate(SpacecraftState s) Get the flow rate.
Frame	getFrame() Get the frame of the acceleration direction.
double	getISP(SpacecraftState s) Get the specific impulse.
AbsoluteDate	getStartDate() Return the maneuver start date (if a date or a DateDetector as been provided).
double	getThrust(SpacecraftState s) Get the thrust.
boolean	isFiring() Returns maneuver status (firing or not).
void	setFiring(boolean isFiring) Set maneuver status.

Methods inherited from class org.orekit.parameter.JacobiansParameterizable

addJacobiansParameter, addJacobiansParameter, addJacobiansParameter, supportsJacobianParameter

Methods inherited from class org.orekit.parameter.Parameterizable

addParameter, getParameters, supportsParameter

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.parameter.IParameterizable

getParameters, supportsParameter

Constructor Detail

VariableThrustManeuver

public VariableThrustManeuver(AbsoluteDate date,
                              double duration,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName)

Constructor for a variable direction in spacecraft frame, thrust and ISP.

Parameters:

date - maneuver date

duration - the duration of the thrust (s) (if negative, the date is considered to be the stop date)

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in satellite frame.

massModel - mass model

partName - name of part firing

VariableThrustManeuver

public VariableThrustManeuver(AbsoluteDate date,
                              double duration,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName,
                              Frame refFrame)

Constructor for a variable direction in provided frame, thrust and ISP.

Parameters:

date - maneuver date

duration - the duration of the thrust (s) (if negative, the date is considered to be the stop date)

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in the frame defined by the user

massModel - mass model

partName - name of part firing

refFrame - the frame of the acceleration direction. SpacecraftFrame class is an unsupported frame.

Throws:

IllegalArgumentException - if input frame is SpacecraftFrame.

VariableThrustManeuver

public VariableThrustManeuver(AbsoluteDate date,
                              double duration,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName,
                              LOFType lofTyp)

Constructor for a variable direction in provided local orbital frame, thrust and ISP expressed in a LocalOrbitalFrame.

Parameters:

date - maneuver date

duration - the duration of the thrust (s) (if negative, the date is considered to be the stop date)

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in the frame defined by the user

massModel - mass model

partName - name of part firing

lofTyp - lofType the LOF type of the acceleration direction

VariableThrustManeuver

public VariableThrustManeuver(EventDetector startEventDetector,
                              EventDetector stopEventDetector,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName)

Constructor for a variable direction in spacecraft frame, thrust and ISP.

Parameters:

startEventDetector - event detector upon which maneuver should starts

stopEventDetector - event detector upon which maneuver should stops

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in satellite frame.

massModel - mass model

partName - name of part firing

VariableThrustManeuver

public VariableThrustManeuver(EventDetector startEventDetector,
                              EventDetector stopEventDetector,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName,
                              Frame refFrame)

Constructor for a variable direction in provided frame, thrust and ISP.

Parameters:

startEventDetector - event detector upon which maneuver should starts

stopEventDetector - event detector upon which maneuver should stops

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in the frame defined by the user

massModel - mass model

partName - name of part firing

refFrame - the frame of the acceleration direction. SpacecraftFrame class is an unsupported frame.

Throws:

IllegalArgumentException - if input frame is SpacecraftFrame.

VariableThrustManeuver

public VariableThrustManeuver(EventDetector startEventDetector,
                              EventDetector stopEventDetector,
                              IDependentVariable<SpacecraftState> variableThrust,
                              IDependentVariable<SpacecraftState> variableIsp,
                              IDependentVectorVariable<SpacecraftState> variableDirection,
                              MassProvider massModel,
                              String partName,
                              LOFType lofTyp)

Constructor for a variable direction in provided local orbital frame, thrust and ISP expressed in a LocalOrbitalFrame.

Parameters:

startEventDetector - event detector upon which maneuver should starts

stopEventDetector - event detector upon which maneuver should stops

variableThrust - the thrust force (N)

variableIsp - engine specific impulse (s)

variableDirection - the acceleration direction in the frame defined by the user

massModel - mass model

partName - name of part firing

lofTyp - lofType the LOF type of the acceleration direction

Method Detail

getThrust

public double getThrust(SpacecraftState s)

Get the thrust.

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

thrust force (N).

getDirection

public Vector3D getDirection(SpacecraftState s)

Get the thrust direction.

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

the thrust direction.

getISP

public double getISP(SpacecraftState s)

Get the specific impulse.

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

specific impulse (s).

getFlowRate

public double getFlowRate(SpacecraftState s)

Get the flow rate.

Parameters:

s - the current state information: date, kinematics, attitude

Returns:

flow rate (negative, kg/s).

getStartDate

public AbsoluteDate getStartDate()

Return the maneuver start date (if a date or a DateDetector as been provided).

Returns:

the maneuver start date if a date or a DateDetector as been provided, null otherwise.

getEndDate

public AbsoluteDate getEndDate()

Return the maneuver stop date (if a date or a DateDetector as been provided).

Returns:

the maneuver stop date if a date or a DateDetector as been provided, null otherwise.

getFrame

public Frame getFrame()

Get the frame of the acceleration direction. Null if the acceleration is expressed by default in the satellite frame.

Returns:

the frame

setFiring

public void setFiring(boolean isFiring)

Set maneuver status. This method is meant to be used if the propagation starts during a maneuver. As a result thrust will be firing at the beginning of the propagation and stops when crossing stop event.

Used in conjunction with isFiring(), the user can stop/restart a propagation during a maneuver.

Parameters:

isFiring - true if propagation should start during the maneuver

isFiring

public boolean isFiring()

Returns maneuver status (firing or not).

Used in conjunction with setFiring(boolean), the user can stop/restart a propagation during a maneuver.

Returns:

true if maneuver is thrust firing.

addContribution

public void addContribution(SpacecraftState s,
                            TimeDerivativesEquations adder)
                     throws OrekitException

Compute the contribution of the force model to the perturbing acceleration.

Specified by:

addContribution in interface ForceModel

Parameters:

s - current state information: date, kinematics, attitude

adder - object where the contribution should be added

Throws:

OrekitException - if some specific error occurs

computeAcceleration

public Vector3D computeAcceleration(SpacecraftState s)
                             throws OrekitException

Description copied from interface: ForceModel

Compute the acceleration due to the force.

Specified by:

computeAcceleration in interface ForceModel

Parameters:

s - current state information: date, kinematics, attitude

Returns:

acceleration in the SpacecraftState frame

Throws:

OrekitException - if some specific error occurs

addDAccDState

public void addDAccDState(SpacecraftState s,
                          double[][] dAccdPos,
                          double[][] dAccdVel)
                   throws OrekitException

Compute acceleration derivatives with respect to state parameters.

Specified by:

addDAccDState in interface IJacobiansParameterizable

Parameters:

s - spacecraft state

dAccdPos - acceleration derivatives with respect to position

dAccdVel - acceleration derivatives with respect to velocity

Throws:

OrekitException - if derivatives cannot be computed

addDAccDParam

public void addDAccDParam(SpacecraftState s,
                          Parameter param,
                          double[] dAccdParam)
                   throws OrekitException

Compute acceleration derivatives with respect to additional parameters.. No jacobian parameter is supported by this force model.

Specified by:

addDAccDParam in interface IJacobiansParameterizable

Parameters:

s - spacecraft state

param - the parameter with respect to which derivatives are required

dAccdParam - acceleration derivatives with respect to specified parameters

Throws:

OrekitException - if derivatives cannot be computed

getEventsDetectors

public EventDetector[] getEventsDetectors()

Description copied from interface: ForceModel

Get the discrete events related to the model.

Specified by:

getEventsDetectors in interface ForceModel

Returns:

array of events detectors or null if the model is not related to any discrete events

computeGradientPosition

public boolean computeGradientPosition()

This method returns true if the acceleration partial derivatives with respect to position have to be computed.

Specified by:

computeGradientPosition in interface GradientModel

Returns:

true if the derivatives have to be computed, false otherwise

computeGradientVelocity

public boolean computeGradientVelocity()

This method returns true if the acceleration partial derivatives with respect to velocity have to be computed.

Specified by:

computeGradientVelocity in interface GradientModel

Returns:

true if the derivatives have to be computed, false otherwise