org.orekit.attitudes
Class NadirPointing

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

All Implemented Interfaces:

Serializable, AttitudeLaw, AttitudeProvider

public class NadirPointing
extends GroundPointing

This class handles nadir pointing attitude provider.

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

The object NadirPointing is guaranteed to be immutable.

Author:

Véronique Pommier-Maurussane

See Also:

GroundPointing, Serialized Form

Constructor Summary

NadirPointing(BodyShape shape)
Creates new instance.

Method Summary

protected Vector3D	getTargetPoint(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target point in specified frame.
TimeStampedPVCoordinates	getTargetPV(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the target point position/velocity in specified frame.

Methods inherited from class org.orekit.attitudes.GroundPointing

getAttitude, getBodyFrame, getBodyShape

Methods inherited from class org.orekit.attitudes.AbstractAttitudeLaw

getAttitude, getSpinDerivativesComputation, setSpinDerivativesComputation

Methods inherited from class java.lang.Object

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

Constructor Detail

NadirPointing

public NadirPointing(BodyShape shape)

Creates new instance.

Parameters:

shape - Body shape

Method Detail

getTargetPV

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

Description copied from class: GroundPointing

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

getTargetPoint

protected 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