org.orekit.forces.maneuvers

Class ConstantThrustManeuver

java.lang.Object

org.apache.commons.math3.ode.AbstractParameterizable

org.orekit.forces.maneuvers.ConstantThrustManeuver

All Implemented Interfaces:

Parameterizable, ParameterizedODE, ForceModel

public class ConstantThrustManeuver
extends AbstractParameterizable
implements ForceModel

This class implements a simple maneuver with constant thrust.

The maneuver is defined by a direction in satelliteframe. The current attitude of the spacecraft, defined by the current spacecraft state, will be used to compute the thrust direction in inertial frame. A typical case for tangential maneuvers is to use a LOF aligned attitude provider for state propagation and a velocity increment along the +X satellite axis.

Author:

Fabien Maussion, Véronique Pommier-Maurussane, Luc Maisonobe

Constructor Summary

Constructors

Constructor and Description
ConstantThrustManeuver(AbsoluteDate date, double duration, double thrust, double isp, Vector3D direction) Simple constructor for a constant direction and constant thrust.

Method Summary

Methods

Modifier and Type	Method and Description
FieldVector3D<DerivativeStructure>	accelerationDerivatives(AbsoluteDate date, Frame frame, FieldVector3D<DerivativeStructure> position, FieldVector3D<DerivativeStructure> velocity, FieldRotation<DerivativeStructure> rotation, DerivativeStructure mass) Compute acceleration derivatives with respect to state parameters.
FieldVector3D<DerivativeStructure>	accelerationDerivatives(SpacecraftState s, String paramName) Compute acceleration derivatives with respect to additional parameters.
void	addContribution(SpacecraftState s, TimeDerivativesEquations adder) Compute the contribution of the force model to the perturbing acceleration.
EventDetector[]	getEventsDetectors() Get the discrete events related to the model.
double	getFlowRate() Get the flow rate.
double	getISP() Get the specific impulse.
double	getParameter(String name)
double	getThrust() Get the thrust.
void	setParameter(String name, double value)

Methods inherited from class org.apache.commons.math3.ode.AbstractParameterizable

complainIfNotSupported, getParametersNames, isSupported

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.math3.ode.Parameterizable

getParametersNames, isSupported

Constructor Detail

ConstantThrustManeuver

public ConstantThrustManeuver(AbsoluteDate date,
                      double duration,
                      double thrust,
                      double isp,
                      Vector3D direction)

Simple constructor for a constant direction and constant thrust.

Parameters:

date - maneuver date

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

thrust - the thrust force (N)

isp - engine specific impulse (s)

direction - the acceleration direction in satellite frame.

Method Detail

getThrust

public double getThrust()

Get the thrust.

Returns:

thrust force (N).

getISP

public double getISP()

Get the specific impulse.

Returns:

specific impulse (s).

getFlowRate

public double getFlowRate()

Get the flow rate.

Returns:

flow rate (negative, kg/s).

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

accelerationDerivatives

public FieldVector3D<DerivativeStructure> accelerationDerivatives(AbsoluteDate date,
                                                         Frame frame,
                                                         FieldVector3D<DerivativeStructure> position,
                                                         FieldVector3D<DerivativeStructure> velocity,
                                                         FieldRotation<DerivativeStructure> rotation,
                                                         DerivativeStructure mass)
                                                           throws OrekitException

Compute acceleration derivatives with respect to state parameters.

The derivatives should be computed with respect to position, velocity and optionnaly mass. The input parameters already take into account the free parameters (6 or 7 depending on derivation with respect to mass being considered or not) and order (always 1). Free parameters at indices 0, 1 and 2 correspond to derivatives with respect to position. Free parameters at indices 3, 4 and 5 correspond to derivatives with respect to velocity. Free parameter at index 6 (if present) corresponds to to derivatives with respect to mass.

Specified by:

accelerationDerivatives in interface ForceModel

Parameters:

date - current date

frame - inertial reference frame for state (both orbit and attitude)

position - position of spacecraft in reference frame

velocity - velocity of spacecraft in reference frame

rotation - orientation (attitude) of the spacecraft with respect to reference frame

mass - spacecraft mass

Returns:

acceleration with all derivatives specified by the input parameters own derivatives

Throws:

OrekitException - if derivatives cannot be computed

accelerationDerivatives

public FieldVector3D<DerivativeStructure> accelerationDerivatives(SpacecraftState s,
                                                         String paramName)
                                                           throws OrekitException

Compute acceleration derivatives with respect to additional parameters.

Specified by:

accelerationDerivatives in interface ForceModel

Parameters:

s - spacecraft state

paramName - name of the parameter with respect to which derivatives are required

Returns:

acceleration with all derivatives specified by the input parameters own derivatives

Throws:

OrekitException - if derivatives cannot be computed

getEventsDetectors

public EventDetector[] getEventsDetectors()

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

getParameter

public double getParameter(String name)
                    throws IllegalArgumentException

Specified by:

getParameter in interface ParameterizedODE

Throws:

IllegalArgumentException

setParameter

public void setParameter(String name,
                double value)
                  throws IllegalArgumentException

Specified by:

setParameter in interface ParameterizedODE

Throws:

IllegalArgumentException