fr.cnes.sirius.patrius.attitudes

Class TwoDirectionAttitudeLaw

java.lang.Object

fr.cnes.sirius.patrius.attitudes.AbstractAttitudeLaw

fr.cnes.sirius.patrius.attitudes.TwoDirectionAttitudeLaw

All Implemented Interfaces:

AttitudeLaw, AttitudeProvider, Serializable

Direct Known Subclasses:

SunPointing

public class TwoDirectionAttitudeLaw
extends AbstractAttitudeLaw

This class implements a generic two directions attitude law. The first direction is aligned with a given satellite axis, the second direction is aligned at best with another given satellite axis. If the two directions are collinear, an exception will be thrown in the getAttitude(PVCoordinatesProvider, AbsoluteDate, Frame) method.

Since:

1.2

Version:

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

Author:

Julie Anton

See Also:

IDirection, Serialized Form

Concurrency :

unconditionally thread safe

Constructor Summary

Constructors

Constructor and Description
TwoDirectionAttitudeLaw(IDirection firstDirection, IDirection secondDirection, Vector3D firstAxis, Vector3D secondAxis) Constructor with default step values for spin and spin derivatives computation using finite differences (0.2s for spin, 0.001s for spin derivative).
TwoDirectionAttitudeLaw(IDirection firstDirection, IDirection secondDirection, Vector3D firstAxis, Vector3D secondAxis, double dtSpin, double dtAcc) Constructor.

Method Summary

Modifier and Type	Method and Description
Attitude	getAttitude(PVCoordinatesProvider pvProv, AbsoluteDate date, Frame frame) Compute the attitude corresponding to an orbital state.
Vector3D	getFirstAxis() Getter for the satellite axis aligned with the first direction.
Vector3D	getSecondAxis() Getter for the satellite axis aligned at best with the second direction.

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, toString, wait, wait, wait

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

computeSpinByFD, computeSpinDerivativeByFD, getAttitude

Constructor Detail

TwoDirectionAttitudeLaw

public TwoDirectionAttitudeLaw(IDirection firstDirection,
                               IDirection secondDirection,
                               Vector3D firstAxis,
                               Vector3D secondAxis)

Constructor with default step values for spin and spin derivatives computation using finite differences (0.2s for spin, 0.001s for spin derivative).
If the two directions are collinear at provided date, an exception will be thrown in the getAttitude(PVCoordinatesProvider, AbsoluteDate, Frame) method.

Parameters:

firstDirection - first direction

secondDirection - second direction

firstAxis - satellite axis that has to be aligned with the fisrt direction

secondAxis - satellite axis that has to be aligned at best with the second direction

TwoDirectionAttitudeLaw

public TwoDirectionAttitudeLaw(IDirection firstDirection,
                               IDirection secondDirection,
                               Vector3D firstAxis,
                               Vector3D secondAxis,
                               double dtSpin,
                               double dtAcc)

Constructor.
If the two directions are collinear at provided date, an exception will be thrown in the getAttitude(PVCoordinatesProvider, AbsoluteDate, Frame) method.

Parameters:

firstDirection - first direction

secondDirection - second direction

firstAxis - satellite axis that has to be aligned with the fisrt direction

secondAxis - satellite axis that has to be aligned at best with the second direction

dtSpin - step for finite differences spin computation

dtAcc - step for finite differences spin derivative computation

Method Detail

getAttitude

public Attitude getAttitude(PVCoordinatesProvider pvProv,
                            AbsoluteDate date,
                            Frame frame)
                     throws PatriusException

Compute the attitude corresponding to an orbital state.
If the two directions of this TwoDirectionAttitudeLaw are collinear at provided date, an exception will be thrown.

Parameters:

pvProv - local position-velocity provider around current date

date - current date

frame - reference frame from which attitude is computed

Returns:

attitude attitude on the specified date and position-velocity state

Throws:

PatriusException - if attitude cannot be computed for provided date

getFirstAxis

public Vector3D getFirstAxis()

Getter for the satellite axis aligned with the first direction.

Returns:

the satellite axis aligned with the first direction

getSecondAxis

public Vector3D getSecondAxis()

Getter for the satellite axis aligned at best with the second direction.

Returns:

the satellite axis aligned at best with the second direction