org.orekit.forces.gravity.variations
Class VariablePotentialAttractionModel

java.lang.Object
  org.orekit.parameter.Parameterizable
      org.orekit.parameter.JacobiansParameterizable
          org.orekit.forces.gravity.variations.VariablePotentialAttractionModel

All Implemented Interfaces:

Serializable, ForceModel, GradientModel, PotentialTimeVariations, IJacobiansParameterizable, IParameterizable

public class VariablePotentialAttractionModel
extends JacobiansParameterizable
implements ForceModel, GradientModel, PotentialTimeVariations

This class represents a variable gravity field. It computes a static potential and a time variable potential. The C and S coefficients array are computed according to the algorithm given by

Since:

1.3

Version:

$Id: VariablePotentialAttractionModel.java 15713 2016-04-01 08:55:06Z bignon $

Author:

Rami Houdroge

See Also:

GRACE / LAGEOS variable model, Serialized Form

Concurrency :

not thread-safe

Concurrency comment :

not thread-safe because of global arrays

Field Summary

static String

RADIUS Parameter name for equatorial radius.

Constructor Summary

VariablePotentialAttractionModel(Frame centralBodyFrame, VariablePotentialCoefficientsProvider provider, int degree, int order)
Variable gravity field force model constructor (static part only).

VariablePotentialAttractionModel(Frame centralBodyFrame, VariablePotentialCoefficientsProvider provider, int degree, int order, int degreePD, int orderPD)
Variable gravity field force model constructor (static part only).

VariablePotentialAttractionModel(Frame centralBodyFrame, VariablePotentialCoefficientsProvider provider, int degree, int order, int degreeOptional, int orderOptional, boolean computeOptionalOnce)
Variable gravity field force model constructor.

VariablePotentialAttractionModel(Frame centralBodyFrame, VariablePotentialCoefficientsProvider provider, int degree, int order, int degreePD, int orderPD, int degreeOptional, int orderOptional, int degreeOptionalPD, int orderOptionalPD, boolean computeOptionalOnce)
Variable gravity field force model constructor.

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(AbsoluteDate date, PVCoordinates pv) Compute acceleration in rotating frame
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.
double	getAe()
EventDetector[]	getEventsDetectors() Get the discrete events related to the model.
double	getMu()
void	updateCoefficientsCandS(AbsoluteDate date) Update the C and the S coefficients for acceleration computation.
void	updateCoefficientsCandSPD(AbsoluteDate date) Update the C and the S coefficients for partial derivatives computation.

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

Field Detail

RADIUS

public static final String RADIUS

Parameter name for equatorial radius.

See Also:

Constant Field Values

Constructor Detail

VariablePotentialAttractionModel

public VariablePotentialAttractionModel(Frame centralBodyFrame,
                                        VariablePotentialCoefficientsProvider provider,
                                        int degree,
                                        int order,
                                        int degreePD,
                                        int orderPD)
                                 throws OrekitException

Variable gravity field force model constructor (static part only).

Parameters:

centralBodyFrame - central rotating body frame

provider - normalized variable coefficients provider

degree - degree for acceleration computation

order - order for acceleration computation

degreePD - degree for partial derivatives computation

orderPD - order for partial derivatives computation

Throws:

OrekitException - if degree too large

VariablePotentialAttractionModel

public VariablePotentialAttractionModel(Frame centralBodyFrame,
                                        VariablePotentialCoefficientsProvider provider,
                                        int degree,
                                        int order)
                                 throws OrekitException

Variable gravity field force model constructor (static part only).

Parameters:

centralBodyFrame - central rotating body frame

provider - normalized variable coefficients provider

degree - degree

order - order

Throws:

OrekitException - if degree too large

VariablePotentialAttractionModel

public VariablePotentialAttractionModel(Frame centralBodyFrame,
                                        VariablePotentialCoefficientsProvider provider,
                                        int degree,
                                        int order,
                                        int degreePD,
                                        int orderPD,
                                        int degreeOptional,
                                        int orderOptional,
                                        int degreeOptionalPD,
                                        int orderOptionalPD,
                                        boolean computeOptionalOnce)
                                 throws OrekitException

Variable gravity field force model constructor. Takes into account optional terms.

Parameters:

centralBodyFrame - central rotating body frame

provider - normalized variable coefficients provider

degree - degree for acceleration computation

order - order for acceleration computation

degreePD - degree for partial derivatives computation

orderPD - order for partial derivatives computation

degreeOptional - max degree of optional terms to take into account for acceleration computation

orderOptional - max order of optional terms to take into account for acceleration computation

degreeOptionalPD - max degree of optional terms to take into account for partial derivatives computation

orderOptionalPD - max order of optional terms to take into account for partial derivatives computation

computeOptionalOnce - true to indicate that coefficients should be computed just once at instantiation. false if coefficients are to be computed every time

Throws:

OrekitException - if degree too large

VariablePotentialAttractionModel

public VariablePotentialAttractionModel(Frame centralBodyFrame,
                                        VariablePotentialCoefficientsProvider provider,
                                        int degree,
                                        int order,
                                        int degreeOptional,
                                        int orderOptional,
                                        boolean computeOptionalOnce)
                                 throws OrekitException

Variable gravity field force model constructor. Takes into account optional terms.

Parameters:

centralBodyFrame - central rotating body frame

provider - normalized variable coefficients provider

degree - degree

order - order

degreeOptional - max degree of optional terms to take into account

orderOptional - max order of optional terms to take into account

computeOptionalOnce - true to indicate that coefficients should be computed just once at instanciation. false if coefficients are to be computed every time.

Throws:

OrekitException - if degree too large

Method Detail

updateCoefficientsCandS

public void updateCoefficientsCandS(AbsoluteDate date)
                             throws OrekitException

Update the C and the S coefficients for acceleration computation.

Specified by:

updateCoefficientsCandS in interface PotentialTimeVariations

Parameters:

date - : date

Throws:

OrekitException - if position cannot be computed in given frame

updateCoefficientsCandSPD

public void updateCoefficientsCandSPD(AbsoluteDate date)
                               throws OrekitException

Update the C and the S coefficients for partial derivatives computation.

Specified by:

updateCoefficientsCandSPD in interface PotentialTimeVariations

Parameters:

date - : date

Throws:

OrekitException - if position cannot be computed in given frame

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

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

computeAcceleration

public Vector3D computeAcceleration(AbsoluteDate date,
                                    PVCoordinates pv)
                             throws OrekitException

Compute acceleration in rotating frame

Parameters:

date - date at which to compute acceleration

pv - pv of spacecraft

Returns:

the acceleration in the rotating frame

Throws:

OrekitException - if acceleration 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

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

getMu

public double getMu()

Returns:

the mu

getAe

public double getAe()

Returns:

the ae

addDAccDState

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

Description copied from interface: IJacobiansParameterizable

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 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