fr.cnes.sirius.patrius.attitudes.directions

Class MomentumDirection

java.lang.Object

fr.cnes.sirius.patrius.attitudes.directions.MomentumDirection

All Implemented Interfaces:

IDirection, Serializable

public final class MomentumDirection
extends Object
implements IDirection

Direction described either:

• 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).
• By a PVCoordinatesProvider. In this case the momentum direction is simply the cross product between the position and the velocity of the PVCoordinatesProvider at the required date.

Since:

1.1

Version:

$Id: MomentumDirection.java 17582 2017-05-10 12:58:16Z bignon $

Author:

Thomas Trapier

See Also:

Serialized Form

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

Constructors

Constructor and Description
MomentumDirection(CelestialBody body) Build a direction from the celestial body around witch the orbit is defined.
MomentumDirection(PVCoordinatesProvider pvProvider) Build a direction from a PVCoordinatesProvider.

Method Summary

Modifier and Type	Method and Description
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 body)

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:

body - the celestial body associated to the orbit

MomentumDirection

public MomentumDirection(PVCoordinatesProvider pvProvider)

Build a direction from a PVCoordinatesProvider. Giving an origin point, the associated vector is the normalised cross product of the position and velocity vectors of the PVCoordinatesProvider at a specific date (momentum vector).

Parameters:

pvProvider - the PVCoordinatesProvider from which the momentum direction should be computed

Method Detail

getVector

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

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 (from origin to target) at the given date in the given frame

Throws:

PatriusException - if some frame specific errors occur

getLine

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

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 half Line of space from the origin position at given date and containing the direction vector

Throws:

PatriusException - if some frame specific errors occur