org.orekit.attitudes
Class GroundPointingWrapper

java.lang.Object
  org.orekit.attitudes.AbstractAttitudeLaw
      org.orekit.attitudes.GroundPointing
          org.orekit.attitudes.GroundPointingWrapper

All Implemented Interfaces:

Serializable, AttitudeLaw, AttitudeLawModifier, AttitudeProvider

Direct Known Subclasses:

YawCompensation, YawSteering

public abstract class GroundPointingWrapper
extends GroundPointing
implements AttitudeLawModifier

This class leverages common parts for compensation modes around ground pointing attitudes.

Author:

Véronique Pommier-Maurussane, Luc Maisonobe

See Also:

Serialized Form

Constructor Summary

GroundPointingWrapper(GroundPointing pGroundPointingLaw)
Creates a new instance.

Method Summary

Attitude	getBaseState(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the base system state at given date, without compensation.
abstract TimeStampedAngularCoordinates	getCompensation(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame, Attitude base) Compute the TimeStampedAngularCoordinates at a given time.
protected Vector3D	getTargetPoint(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target point in specified frame.
protected TimeStampedPVCoordinates	getTargetPV(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target point position/velocity in specified frame.
AttitudeLaw	getUnderlyingAttitudeLaw() Get the underlying (ground pointing) attitude provider.
void	setSpinDerivativesComputation(boolean computeSpinDerivatives) Method to activate spin derivative computation.

Methods inherited from class org.orekit.attitudes.GroundPointing

getAttitude, getBodyFrame, getBodyShape

Methods inherited from class org.orekit.attitudes.AbstractAttitudeLaw

getAttitude, getSpinDerivativesComputation

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.attitudes.AttitudeProvider

getAttitude, getAttitude

Constructor Detail

GroundPointingWrapper

public GroundPointingWrapper(GroundPointing pGroundPointingLaw)

Creates a new instance.

Parameters:

pGroundPointingLaw - ground pointing attitude provider without compensation

Method Detail

getUnderlyingAttitudeLaw

public final AttitudeLaw getUnderlyingAttitudeLaw()

Get the underlying (ground pointing) attitude provider.

Specified by:

getUnderlyingAttitudeLaw in interface AttitudeLawModifier

Returns:

underlying attitude provider, which in this case is a GroundPointing instance

getTargetPoint

protected final Vector3D getTargetPoint(PVCoordinatesProvider pvProv,
                                        AbsoluteDate date,
                                        Frame frame)
                                 throws OrekitException

Compute the target point in specified frame.

Specified by:

getTargetPoint in class GroundPointing

Parameters:

pvProv - provider for PV coordinates

date - date at which target point is requested

frame - frame in which observed ground point should be provided

Returns:

observed ground point position in specified frame

Throws:

OrekitException - if some specific error occurs, such as no target reached

getTargetPV

protected final TimeStampedPVCoordinates getTargetPV(PVCoordinatesProvider pvProv,
                                                     AbsoluteDate date,
                                                     Frame frame)
                                              throws OrekitException

Compute the target point position/velocity in specified frame.

The default implementation use a simple centered two points finite differences scheme, it may be replaced by more accurate models in specialized implementations.

In the case where the point is computed at a date corresponding to the lower/upper bound of the ephemeris, the finite differences scheme used is either 1st order forward or backward.

Overrides:

getTargetPV in class GroundPointing

Parameters:

pvProv - provider for PV coordinates

date - date at which target point is requested

frame - frame in which observed ground point should be provided

Returns:

observed ground point position/velocity in specified frame

Throws:

OrekitException - if some specific error occurs, such as no target reached

getBaseState

public final Attitude getBaseState(PVCoordinatesProvider pvProv,
                                   AbsoluteDate date,
                                   Frame frame)
                            throws OrekitException

Compute the base system state at given date, without compensation.

Parameters:

pvProv - provider for PV coordinates

date - date at which state is requested

frame - reference frame from which attitude is computed

Returns:

satellite base attitude state, i.e without compensation.

Throws:

OrekitException - if some specific error occurs

getCompensation

public abstract TimeStampedAngularCoordinates getCompensation(PVCoordinatesProvider pvProv,
                                                              AbsoluteDate date,
                                                              Frame frame,
                                                              Attitude base)
                                                       throws OrekitException

Compute the TimeStampedAngularCoordinates at a given time.

Parameters:

pvProv - provider for PV coordinates

date - date at which rotation is requested

frame - reference frame from which attitude is computed

base - base satellite attitude in given frame.

Returns:

compensation rotation at date, i.e rotation between non compensated attitude state and compensated state.

Throws:

OrekitException - if some specific error occurs

setSpinDerivativesComputation

public void setSpinDerivativesComputation(boolean computeSpinDerivatives)
                                   throws OrekitException

Method to activate spin derivative computation.

Spin derivatives computation applies to provided law groundPointingLaw.

Specified by:

setSpinDerivativesComputation in interface AttitudeProvider

Overrides:

setSpinDerivativesComputation in class AbstractAttitudeLaw

Parameters:

computeSpinDerivatives - true if spin derivatives should be computed

Throws:

OrekitException - if spin derivatives can not be computed