fr.cnes.sirius.patrius.attitudes

Class NadirPointing

java.lang.Object

fr.cnes.sirius.patrius.attitudes.AbstractAttitudeLaw

fr.cnes.sirius.patrius.attitudes.AbstractGroundPointing

fr.cnes.sirius.patrius.attitudes.NadirPointing

All Implemented Interfaces:

AttitudeLaw, AttitudeProvider, Serializable

public class NadirPointing
extends AbstractGroundPointing

This class handles nadir pointing attitude provider.

This class represents the attitude provider where (by default) the satellite z axis is pointing to the vertical of the ground point under satellite.

The object NadirPointing is guaranteed to be immutable.

This class is restricted to be used with EllipsoidBodyShape.

Author:

Véronique Pommier-Maurussane

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
NadirPointing(EllipsoidBodyShape shape) Creates new instance.
NadirPointing(EllipsoidBodyShape shape, Vector3D losInSatFrameVec, Vector3D losNormalInSatFrameVec) Constructor.
NadirPointing(EllipsoidBodyShape shape, Vector3D losInSatFrameVec, Vector3D losNormalInSatFrameVec, double deltaT) Constructor.

Method Summary

Modifier and Type	Method and Description
protected Vector3D	getTargetPosition(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target ground point position in specified frame.
TimeStampedPVCoordinates	getTargetPV(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target point position/velocity in specified frame.
String	toString()

Methods inherited from class fr.cnes.sirius.patrius.attitudes.AbstractGroundPointing

getAttitude, getBodyFrame, getBodyShape, getLosInSatFrame, getLosNormalInSatFrame

Methods inherited from class fr.cnes.sirius.patrius.attitudes.AbstractAttitudeLaw

getSpinDerivativesComputation, setSpinDerivativesComputation

Methods inherited from class java.lang.Object

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

Methods inherited from interface fr.cnes.sirius.patrius.attitudes.AttitudeProvider

computeSpinByFD, computeSpinDerivativeByFD, getAttitude

Constructor Detail

NadirPointing

public NadirPointing(EllipsoidBodyShape shape)

Creates new instance.

Parameters:

shape - Body shape

NadirPointing

public NadirPointing(EllipsoidBodyShape shape,
                     Vector3D losInSatFrameVec,
                     Vector3D losNormalInSatFrameVec)

Constructor. Create a NadirPointing attitude provider with specified los axis in satellite frame.

Parameters:

shape - Body shape

losInSatFrameVec - LOS in satellite frame axis

losNormalInSatFrameVec - LOS normal axis in satellite frame

NadirPointing

public NadirPointing(EllipsoidBodyShape shape,
                     Vector3D losInSatFrameVec,
                     Vector3D losNormalInSatFrameVec,
                     double deltaT)

Constructor. Create a NadirPointing attitude provider with specified los axis in satellite frame.

Parameters:

shape - Body shape

losInSatFrameVec - LOS in satellite frame axis

losNormalInSatFrameVec - LOS normal axis in satellite frame

deltaT - the delta-T used to compute target PVCoordinates by finite differences

Method Detail

getTargetPV

public TimeStampedPVCoordinates getTargetPV(PVCoordinatesProvider pvProv,
                                            AbsoluteDate date,
                                            Frame frame)
                                     throws PatriusException

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.

The calculated intersection velocity corresponds to the "virtual" intersection point velocity between the satellite los and the Earth, not the velocity of the physical point.

Overrides:

getTargetPV in class AbstractGroundPointing

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:

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

getTargetPosition

protected Vector3D getTargetPosition(PVCoordinatesProvider pvProv,
                                     AbsoluteDate date,
                                     Frame frame)
                              throws PatriusException

Compute the target ground point position in specified frame.

Specified by:

getTargetPosition in class AbstractGroundPointing

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:

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

toString

public String toString()

Overrides:

toString in class Object