org.orekit.propagation.numerical

Class Jacobianizer

java.lang.Object

org.orekit.propagation.numerical.Jacobianizer

public class Jacobianizer
extends Object

Class helping implementation of partial derivatives in force models implementations.

For better performances, force models implementations should compute their partial derivatives analytically. However, in some cases, it may be difficult. This class allows to compute the derivatives by finite differences relying only on the basic acceleration.

Author:

Véronique Pommier-Maurussane, Luc Maisonobe

Constructor Summary

Constructors

Constructor and Description
Jacobianizer(ForceModel forceModel, double mu, Collection<ParameterConfiguration> paramsAndSteps, double hPos) Simple constructor.

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 and derivatives with respect to state.
FieldVector3D<DerivativeStructure>	accelerationDerivatives(SpacecraftState s, String paramName) Compute acceleration and derivatives with respect to parameter.

Methods inherited from class java.lang.Object

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

Constructor Detail

Jacobianizer

public Jacobianizer(ForceModel forceModel,
            double mu,
            Collection<ParameterConfiguration> paramsAndSteps,
            double hPos)

Simple constructor.

Parameters:

forceModel - force model instance to wrap

mu - central attraction coefficient (m³/s²)

paramsAndSteps - collection of parameters and their associated steps

hPos - step used for finite difference computation with respect to spacecraft position (m)

Method Detail

accelerationDerivatives

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

Compute acceleration and derivatives with respect to state.

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 derivatives

Throws:

OrekitException - if the underlying force models cannot compute the acceleration

accelerationDerivatives

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

Compute acceleration and derivatives with respect to parameter.

Parameters:

s - current state

paramName - parameter with respect to which derivation is desired

Returns:

acceleration with derivatives

Throws:

OrekitException - if the underlying force models cannot compute the acceleration or the parameter is not supported