org.orekit.attitudes.directions
Class MomentumDirection

java.lang.Object
  org.orekit.attitudes.directions.MomentumDirection

All Implemented Interfaces:

IDirection

public final class MomentumDirection
extends Object
implements IDirection

Direction described by a celestial body (the reference body of the orbit). For a given PVCoordinatesProvider origin point the associated vector is the normalised cross product of the position to the celestial body and the velocity (momentum vector).

Since:

1.1

Version:

$Id: MomentumDirection.java 13175 2015-05-06 13:44:38Z trapier $

Author:

Thomas Trapier

Concurrency :

conditionally thread-safe

Concurrency comment :

The use of a celestial body linked to the tree of frames makes this class thread-safe only if the underlying CelestialBody is too.

Constructor Summary

MomentumDirection(CelestialBody inBody)
Build a direction from the celestial body around witch the orbit is defined.

Method Summary

Line	getLine(PVCoordinatesProvider origin, AbsoluteDate date, Frame frame) Provides the line containing the origin (given PV coordinates) and directed by the direction vector.
Vector3D	getVector(PVCoordinatesProvider origin, AbsoluteDate date, Frame frame) Provides the direction vector at a given date in a given frame.

Methods inherited from class java.lang.Object

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

Constructor Detail

MomentumDirection

public MomentumDirection(CelestialBody inBody)

Build a direction from the celestial body around witch the orbit is defined. Giving an origin point, the associated vector is the normalised cross product of the position to the celestial body associated to the orbit and the velocity at a specific date (momentum vector).

Parameters:

inBody - the celestial body associated to the orbit

Method Detail

getVector

public Vector3D getVector(PVCoordinatesProvider origin,
                          AbsoluteDate date,
                          Frame frame)
                   throws OrekitException

Provides the direction vector at a given date in a given frame.

Specified by:

getVector in interface IDirection

Parameters:

origin - the current coordinates of the origin point of the direction (may be null, in that specific case, the origin of the direction is the frame origin).

date - the date

frame - the frame to project the vector's coordinates

Returns:

the direction vector at the given date in the given frame

Throws:

OrekitException - if some frame specific errors occur

getLine

public Line getLine(PVCoordinatesProvider origin,
                    AbsoluteDate date,
                    Frame frame)
             throws OrekitException

Provides the line containing the origin (given PV coordinates) and directed by the direction vector.

Specified by:

getLine in interface IDirection

Parameters:

origin - the origin of the direction

date - the current date

frame - the expression frame of the line

Returns:

the Line of space containing the origin and direction vector

Throws:

OrekitException - if some frame specific errors occur