org.orekit.attitudes
Class AbstractIsisSpinBiasSlew

java.lang.Object
  org.orekit.attitudes.AbstractSlew
      org.orekit.attitudes.AbstractIsisSpinBiasSlew

All Implemented Interfaces:

Serializable, AttitudeLeg, AttitudeProvider, Slew

Direct Known Subclasses:

IsisAnalyticalSpinBiasSlew, IsisNumericalSpinBiasSlew

public abstract class AbstractIsisSpinBiasSlew
extends AbstractSlew

Abstract class for ISIS spin bias slew: slew with trapezoidal angular velocity profile.

Since:

3.3

Version:

$Id: AbstractIsisSpinBiasSlew.java 16755 2016-10-07 15:47:40Z bignon $

Author:

Emmanuel Bignon

See Also:

Serialized Form

Concurrency :

not thread safe

Field Summary

protected double	accelDuration Duration of the acceleration phase.
protected double	accelMax Value of the acceleration step during the first phase.
protected double	decelDuration Duration of the deceleration phase.
protected double	decelMax Value of the deceleration step during the last phase (assumed > 0).
protected double	dtSCAO Time step.
protected double	durationWoTranq Duration of the spin bias slew, excluding the tranquillisation phase.
protected TabulatedAttitude	ephem Attitude ephemerides of the slew, including the tranquillisation phase.
protected AbsoluteDate	initialDate Initial date of the slew.
protected Frame	refFrame Reference frame.
protected double	slewAngle Angle of the rotation associated to the spin bias slew.
protected Vector3D	slewAxis Axis of the rotation associated to the spin bias slew.
protected boolean	spinDerivativesComputation Flag to indicate if spin derivation computation is activated.

Fields inherited from class org.orekit.attitudes.AbstractSlew

computed, currentProvider, fLaw, iLaw, intervalOfValidity

Constructor Summary

AbstractIsisSpinBiasSlew(AttitudeProvider initialLawIn, AttitudeProvider finalLawIn, AbsoluteDate initialDateIn, double dtSCAOIn, double thetaMaxAllowedIn, double durationMaxIn, double dtConvergenceThresholdIn, double[][] inertiaMatrixIn, double rwTorqueAllocAccelIn, double rwTorqueAllocDecelIn, double rwDeltaMomentumAllocIn, double[][] rwMatrixIn, double tranquillisationTimeIn)
Constructor with default maximum number of iterations allowed for slew duration computation's convergence.

AbstractIsisSpinBiasSlew(AttitudeProvider initialLawIn, AttitudeProvider finalLawIn, AbsoluteDate initialDateIn, double dtSCAOIn, double thetaMaxAllowedIn, double durationMaxIn, double dtConvergenceThresholdIn, double[][] inertiaMatrixIn, double rwTorqueAllocAccelIn, double rwTorqueAllocDecelIn, double rwDeltaMomentumAllocIn, double[][] rwMatrixIn, double tranquillisationTimeIn, int maxIterationsNumberIn)
Constructor.

Method Summary

double	computeDuration(PVCoordinatesProvider pvProv) Computes the slew duration.
Attitude	getAttitude(AbsoluteDate date, Frame frame) Compute the attitude.
void	setSpinDerivativesComputation(boolean computeSpinDerivatives) Method to activate spin derivative computation.

Methods inherited from class org.orekit.attitudes.AbstractSlew

getAttitude, getAttitude, getDuration, getTimeInterval

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.attitudes.Slew

compute

Field Detail

initialDate

protected final AbsoluteDate initialDate

Initial date of the slew.

refFrame

protected final Frame refFrame

Reference frame.

dtSCAO

protected final double dtSCAO

Time step.

spinDerivativesComputation

protected boolean spinDerivativesComputation

Flag to indicate if spin derivation computation is activated.

slewAngle

protected double slewAngle

Angle of the rotation associated to the spin bias slew.

slewAxis

protected Vector3D slewAxis

Axis of the rotation associated to the spin bias slew.

durationWoTranq

protected double durationWoTranq

Duration of the spin bias slew, excluding the tranquillisation phase.

accelMax

protected double accelMax

Value of the acceleration step during the first phase.

decelMax

protected double decelMax

Value of the deceleration step during the last phase (assumed > 0).

accelDuration

protected double accelDuration

Duration of the acceleration phase.

decelDuration

protected double decelDuration

Duration of the deceleration phase.

ephem

protected TabulatedAttitude ephem

Attitude ephemerides of the slew, including the tranquillisation phase.

Constructor Detail

AbstractIsisSpinBiasSlew

public AbstractIsisSpinBiasSlew(AttitudeProvider initialLawIn,
                                AttitudeProvider finalLawIn,
                                AbsoluteDate initialDateIn,
                                double dtSCAOIn,
                                double thetaMaxAllowedIn,
                                double durationMaxIn,
                                double dtConvergenceThresholdIn,
                                double[][] inertiaMatrixIn,
                                double rwTorqueAllocAccelIn,
                                double rwTorqueAllocDecelIn,
                                double rwDeltaMomentumAllocIn,
                                double[][] rwMatrixIn,
                                double tranquillisationTimeIn)

Constructor with default maximum number of iterations allowed for slew duration computation's convergence.

Parameters:

initialLawIn - attitude law before the slew

finalLawIn - attitude law after the slew

initialDateIn - slew initial date

dtSCAOIn - time step (s)

thetaMaxAllowedIn - maximum slew angular amplitude allowed (rad)

durationMaxIn - maximum duration expected for the slew, including the tranquilisation phase (s)

dtConvergenceThresholdIn - convergence threshold for the iterative computation of the slew duration (s)

inertiaMatrixIn - satellite inertia matrix in satellite reference frame (kg.m^2)

rwTorqueAllocAccelIn - torque allocation for each RW during the acceleration phase (N.m)

rwTorqueAllocDecelIn - torque allocation for each RW during the deceleration phase (assumed > 0) (N.m)

rwDeltaMomentumAllocIn - angular momentum allocation for each RW during the manoeuvre (N.m.s)

rwMatrixIn - cosine directors matrix of the reaction wheels in the satellite reference frame. Matrix 3xN_RW with N_RW wheels (Reaction wheels spin axes written in column in the satellite reference frame).

tranquillisationTimeIn - tranquilisation time after the end of the slew (s)

AbstractIsisSpinBiasSlew

public AbstractIsisSpinBiasSlew(AttitudeProvider initialLawIn,
                                AttitudeProvider finalLawIn,
                                AbsoluteDate initialDateIn,
                                double dtSCAOIn,
                                double thetaMaxAllowedIn,
                                double durationMaxIn,
                                double dtConvergenceThresholdIn,
                                double[][] inertiaMatrixIn,
                                double rwTorqueAllocAccelIn,
                                double rwTorqueAllocDecelIn,
                                double rwDeltaMomentumAllocIn,
                                double[][] rwMatrixIn,
                                double tranquillisationTimeIn,
                                int maxIterationsNumberIn)

Constructor.

Parameters:

initialLawIn - attitude law before the slew

finalLawIn - attitude law after the slew

initialDateIn - initial date of the slew

dtSCAOIn - time step (s)

thetaMaxAllowedIn - maximum slew angular amplitude allowed (rad)

durationMaxIn - maximum duration expected for the slew, including the tranquilisation phase (s)

dtConvergenceThresholdIn - convergence threshold for the iterative computation of the slew duration (s)

inertiaMatrixIn - satellite inertia matrix in satellite reference frame (kg.m^2)

rwTorqueAllocAccelIn - torque allocation for each RW during the acceleration phase (N.m)

rwTorqueAllocDecelIn - torque allocation for each RW during the deceleration phase (assumed > 0) (N.m)

rwDeltaMomentumAllocIn - angular momentum allocation for each RW during the manoeuvre (N.m.s)

rwMatrixIn - cosine directors matrix of the reaction wheels in the satellite reference frame. Matrix 3xN_RW with N_RW wheels (Reaction wheels spin axes written in column in the satellite reference frame).

tranquillisationTimeIn - tranquilisation time after the end of the slew (s)

maxIterationsNumberIn - maximum number of iterations allowed for slew duration computation's convergence

Method Detail

computeDuration

public double computeDuration(PVCoordinatesProvider pvProv)
                       throws OrekitException

Computes the slew duration.

Parameters:

pvProv - PV coordinates provider

Returns:

slew duration

Throws:

OrekitException - thrown if an error occurs during attitudes computation

getAttitude

public Attitude getAttitude(AbsoluteDate date,
                            Frame frame)
                     throws OrekitException

Compute the attitude.

Parameters:

date - : current date

frame - : reference frame from which attitude is computed

Returns:

attitude : attitude at the specified date

Throws:

OrekitException - orekit exception

setSpinDerivativesComputation

public void setSpinDerivativesComputation(boolean computeSpinDerivatives)

Method to activate spin derivative computation.

Parameters:

computeSpinDerivatives - true if spin derivatives should be computed