org.orekit.attitudes
Class TwoSpinBiasSlew

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

All Implemented Interfaces:

Serializable, AttitudeLeg, AttitudeProvider, Slew

public class TwoSpinBiasSlew
extends AbstractSlew

This class extends the AbstractSlew.

The two spin bias slew computes the attitude of the satellite from initial and final attitude laws, the parameters of the two angular velocity fields, plus the time step as well as the stabilization margin.
The angular velocity depends on the value of the slew angle.
Like all the other attitude legs, its interval of validity has closed endpoints.

Since:

2.1

Version:

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

Author:

Tiziana Sabatini

See Also:

Serialized Form

Concurrency :

not thread safe

Concurrency comment :

this class is not thread safe because the local attitude ephemeris is changed.

Field Summary

Fields inherited from class org.orekit.attitudes.AbstractSlew

computed, currentProvider, fLaw, iLaw, intervalOfValidity

Constructor Summary

TwoSpinBiasSlew(AttitudeProvider initialLaw, AttitudeProvider targetLaw, AbsoluteDate initialDate, double dtSCAOIn, double thetaMaxIn, double tauIn, double epsInRall, double omegaHigh, double thetaSwitch, double epsOutRall, double omegaLow, double tStab)
This class extends the AbstractSlew.

Method Summary

void	compute(PVCoordinatesProvider pvProv) Compute the slew corresponding to an orbital state.
double	computeDuration(PVCoordinatesProvider pvProv) Computes the actual slew duration.
double	computeMaxDuration() Estimate the maximum duration of the slew, before computing it.
Attitude	getAttitude(AbsoluteDate date, Frame frame) Compute the attitude.
TabulatedAttitude	getEphemeris() Get the attitude ephemeris representing the slew
Vector3D	getSpinDerivatives(AbsoluteDate date, Frame frame) get the spin derivatives (default implementation : finite differences differentiator).
Vector3DFunction	getSpinFunction(Frame frame, AbsoluteDate zeroAbscissa)
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

Constructor Detail

TwoSpinBiasSlew

public TwoSpinBiasSlew(AttitudeProvider initialLaw,
                       AttitudeProvider targetLaw,
                       AbsoluteDate initialDate,
                       double dtSCAOIn,
                       double thetaMaxIn,
                       double tauIn,
                       double epsInRall,
                       double omegaHigh,
                       double thetaSwitch,
                       double epsOutRall,
                       double omegaLow,
                       double tStab)
                throws OrekitException

This class extends the AbstractSlew.

The two spin bias slew computes the attitude of the satellite from initial and final attitude laws, the parameters of the two angular velocity fields, plus the time step as well as the stabilization margin.
The angular velocity depends on the value of the slew angle.

Parameters:

initialLaw - the AttitudeProvider representing the attitude law before the slew.

targetLaw - the AttitudeProvider representing the attitude law after the slew.

initialDate - the initial date of the slew.

dtSCAOIn - (dtScao) the time step [s].

thetaMaxIn - (angleMax) the limit of validity of the maneuver amplitude [rad].

tauIn - (τ) the time constant of the filter [s].

epsInRall - (seuilEntree) initial orientation error threshold [rad].

omegaHigh - (biaisVitesse) the high angular velocity value [rad/s].

thetaSwitch - (seuil) the threshold for the low/high angular velocity switch [rad].

epsOutRall - (seuilSortie) final orientation error threshold [rad].

omegaLow - (biaisVitesseBas) the low angular velocity value [rad/s].

tStab - (margeStabilisation) the stabilisation margin [s].

Throws:

OrekitException - when the sampling step in not valid

Method Detail

compute

public void compute(PVCoordinatesProvider pvProv)
             throws OrekitException

Description copied from interface: Slew

Compute the slew corresponding to an orbital state.

Parameters:

pvProv - : local position-velocity provider around current date

Throws:

OrekitException - orekit exception

computeDuration

public double computeDuration(PVCoordinatesProvider pvProv)
                       throws OrekitException

Computes the actual slew duration.

Parameters:

pvProv - the PV coordinates provider

Returns:

the actual slew duration

Throws:

OrekitException - when an error occurs during attitudes computation

computeMaxDuration

public double computeMaxDuration()

Estimate the maximum duration of the slew, before computing it.

Returns:

the estimated maximum duration of the slew.

getAttitude

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

Description copied from interface: Slew

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

getEphemeris

public TabulatedAttitude getEphemeris()

Get the attitude ephemeris representing the slew

Returns:

the ephemeris

setSpinDerivativesComputation

public void setSpinDerivativesComputation(boolean computeSpinDerivatives)

Method to activate spin derivative computation.

Parameters:

computeSpinDerivatives - true if spin derivatives should be computed

getSpinDerivatives

public Vector3D getSpinDerivatives(AbsoluteDate date,
                                   Frame frame)
                            throws OrekitException

get the spin derivatives (default implementation : finite differences differentiator).

Parameters:

date - the date to compute derivative of spin

frame - reference frame from which derivative of spin is computed

Returns:

the spin derivative

Throws:

OrekitException - if spin derivative cannot be computed

getSpinFunction

public Vector3DFunction getSpinFunction(Frame frame,
                                        AbsoluteDate zeroAbscissa)

Parameters:

frame - reference frame from which spin function of date is computed

zeroAbscissa - the date for which x=0 for spin function of date

Returns:

spin function of date relative