fr.cnes.sirius.patrius.stela.orbits

Class StelaEquinoctialOrbit

java.lang.Object

fr.cnes.sirius.patrius.orbits.Orbit

fr.cnes.sirius.patrius.stela.orbits.StelaEquinoctialOrbit

All Implemented Interfaces:

PVCoordinatesProvider, TimeInterpolable<Orbit>, TimeShiftable<Orbit>, TimeStamped, Serializable

public final class StelaEquinoctialOrbit
extends Orbit

This class handles Stela equinoctial orbital parameters, which can support both circular and equatorial orbits.

The parameters used internally are the Stela equinoctial elements (see StelaEquinoctialParameters for more information.

Since:

1.3

Version:

$Id$

Author:

Tiziana Sabatini

See Also:

Serialized Form

Concurrency :

immutable

Constructor Summary

Constructors

Constructor and Description
StelaEquinoctialOrbit(double aIn, double exIn, double eyIn, double ixIn, double iyIn, double lMIn, Frame frame, AbsoluteDate date, double mu) Creates a new instance.
StelaEquinoctialOrbit(double aIn, double exIn, double eyIn, double ixIn, double iyIn, double lMIn, Frame frame, AbsoluteDate date, double mu, boolean isCorrectedIn) Creates a new instance.
StelaEquinoctialOrbit(IOrbitalParameters params, Frame frame, AbsoluteDate date) Creates a new instance.
StelaEquinoctialOrbit(Orbit op) Constructor from any kind of orbital parameters with correction when inclination is close to 180°
StelaEquinoctialOrbit(Orbit op, boolean isCorrectedIn) Constructor from any kind of orbital parameters.
StelaEquinoctialOrbit(PVCoordinates pvCoordinates, Frame frame, AbsoluteDate date, double mu) Constructor from cartesian parameters.

Method Summary

Modifier and Type	Method and Description
void	addKeplerContribution(PositionAngle type, double gm, double[] pDot) Call the method orbitAddKeplerContribution(PositionAngle, double, double[]) implemented in inherited classes of Orbit.
protected double[][]	computeJacobianEccentricWrtCartesian() Compute the Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian parameters.
protected double[][]	computeJacobianMeanWrtCartesian() Compute the Jacobian of the orbital parameters with mean angle with respect to the Cartesian parameters.
protected double[][]	computeJacobianTrueWrtCartesian() Compute the Jacobian of the orbital parameters with true angle with respect to the Cartesian parameters.
boolean	equals(Object object) Test for the equality of two orbits.
double	getA() Get the semi-major axis.
double	getE() Get the eccentricity.
double	getEquinoctialEx() Get the first component of the eccentricity vector.
double	getEquinoctialEy() Get the second component of the eccentricity vector.
StelaEquinoctialParameters	getEquinoctialParameters() Getter for underlying equinoctial parameters.
double	getHx() Get hx = ix / (2 * cos(i/2)), where ix is the first component of the inclination vector.
double	getHy() Get hy = iy / (2 * cos(i/2)), where iy is the second component of the inclination vector.
double	getI() Get the inclination.
double	getIx() Get the first component of the inclination vector.
double	getIy() Get the second component of the inclination vector.
double	getLE() Get the eccentric longitude argument.
double	getLM() Get the mean longitude argument.
double	getLv() Get the true longitude argument.
double	getN() Get the mean motion.
IOrbitalParameters	getParameters() Get underlying orbital parameters.
PVCoordinates	getPVCoordinates(AbsoluteDate otherDate, Frame otherFrame) Get the PVCoordinates of the body in the selected frame.
OrbitType	getType() Get the orbit type.
int	hashCode() Get a hashCode for the orbit.
protected PVCoordinates	initPVCoordinates() Compute the position/velocity coordinates from the canonical parameters.
Orbit	interpolate(AbsoluteDate date, Collection<Orbit> sample) Get an interpolated instance.
double	kepEq(double e, double mMod) Implementation of a Kepler Equation Solver described by F.
double[]	mapOrbitToArray() Substitute for Orekit's OrbitTypes.mapOrbitToArray.
protected void	orbitAddKeplerContribution(PositionAngle type, double gm, double[] pDot) Add the contribution of the Keplerian motion to parameters derivatives
protected Orbit	orbitShiftedBy(double dt) Get a time-shifted orbit.

Methods inherited from class fr.cnes.sirius.patrius.orbits.Orbit

createInverseJacobian, ensurePseudoInertialFrame, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, getDate, getFrame, getJacobian, getJacobian, getJacobian, getJacobian, getJacobianWrtCartesian, getJacobianWrtParameters, getJacobianWrtParametersEccentric, getJacobianWrtParametersMean, getJacobianWrtParametersTrue, getKeplerianMeanMotion, getKeplerianPeriod, getKeplerianTransitionMatrix, getMu, getNativeFrame, getPVCoordinates, getPVCoordinates, setJacobianWrtParametersEccentric, setJacobianWrtParametersMean, setJacobianWrtParametersTrue, shiftedBy

Methods inherited from class java.lang.Object

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

Constructor Detail

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(IOrbitalParameters params,
                             Frame frame,
                             AbsoluteDate date)

Creates a new instance.

Parameters:

params - orbital parameters

frame - the frame in which the parameters are defined

date - date of the orbital parameters

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(double aIn,
                             double exIn,
                             double eyIn,
                             double ixIn,
                             double iyIn,
                             double lMIn,
                             Frame frame,
                             AbsoluteDate date,
                             double mu)

Creates a new instance. Inclination is corrected when close to 180°

Parameters:

aIn - the semi-major axis (m)

exIn - the e cos(ω + Ω), first component of eccentricity vector

eyIn - the e sin(ω + Ω), second component of eccentricity vector

ixIn - the sin(i/2) cos(Ω), first component of inclination vector

iyIn - the sin(i/2) sin(Ω), second component of inclination vector

lMIn - the M + ω + Ω, mean longitude argument (rad)

frame - frame in which the parameters are defined

date - the date of the orbital parameters

mu - the central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(double aIn,
                             double exIn,
                             double eyIn,
                             double ixIn,
                             double iyIn,
                             double lMIn,
                             Frame frame,
                             AbsoluteDate date,
                             double mu,
                             boolean isCorrectedIn)

Creates a new instance.

Parameters:

aIn - semi-major axis (m)

exIn - e cos(ω + Ω), first component of eccentricity vector

eyIn - e sin(ω + Ω), second component of eccentricity vector

ixIn - sin(i/2) cos(Ω), first component of inclination vector

iyIn - sin(i/2) sin(Ω), second component of inclination vector

lMIn - M + ω + Ω, mean longitude argument (rad)

frame - the frame in which the parameters are defined

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

isCorrectedIn - Has the correction when inclination is around 180° to be done

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(PVCoordinates pvCoordinates,
                             Frame frame,
                             AbsoluteDate date,
                             double mu)

Constructor from cartesian parameters. No correction when i around 180°.

Parameters:

pvCoordinates - position and velocity

frame - the frame in which are defined the PVCoordinates

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(Orbit op)

Constructor from any kind of orbital parameters with correction when inclination is close to 180°

Parameters:

op - orbital parameters to copy

StelaEquinoctialOrbit

public StelaEquinoctialOrbit(Orbit op,
                             boolean isCorrectedIn)

Constructor from any kind of orbital parameters.

Parameters:

op - orbital parameters to copy

isCorrectedIn - Has the correction when inclination is around 180° to be done

Method Detail

getParameters

public IOrbitalParameters getParameters()

Get underlying orbital parameters.

Specified by:

getParameters in class Orbit

Returns:

orbital parameters

getEquinoctialParameters

public StelaEquinoctialParameters getEquinoctialParameters()

Getter for underlying equinoctial parameters.

Returns:

equinoctial parameters

interpolate

public Orbit interpolate(AbsoluteDate date,
                         Collection<Orbit> sample)

Get an interpolated instance.

Note that the state of the current instance may not be used in the interpolation process, only its type and non interpolable fields are used (for example central attraction coefficient or frame when interpolating orbits). The interpolable fields taken into account are taken only from the states of the sample points. So if the state of the instance must be used, the instance should be included in the sample points.

Not implemented yet.

Parameters:

date - interpolation date

sample - sample points on which interpolation should be done

Returns:

a new instance, interpolated at specified date

getType

public OrbitType getType()

Get the orbit type.

Not implemented yet.

Specified by:

getType in class Orbit

Returns:

orbit type

getA

public double getA()

Get the semi-major axis.

Specified by:

getA in class Orbit

Returns:

semi-major axis (m)

getEquinoctialEx

public double getEquinoctialEx()

Get the first component of the eccentricity vector.

Specified by:

getEquinoctialEx in class Orbit

Returns:

e cos(ω + Ω), first component of the eccentricity vector

getEquinoctialEy

public double getEquinoctialEy()

Get the second component of the eccentricity vector.

Specified by:

getEquinoctialEy in class Orbit

Returns:

e sin(ω + Ω), second component of the eccentricity vector

getHx

public double getHx()

Get hx = ix / (2 * cos(i/2)), where ix is the first component of the inclination vector. Another formulation is hx = tan(i/2) cos(Ω)

Specified by:

getHx in class Orbit

Returns:

first component of the inclination vector

getHy

public double getHy()

Get hy = iy / (2 * cos(i/2)), where iy is the second component of the inclination vector. Another formulation is hy = tan(i/2) sin(Ω)

Specified by:

getHy in class Orbit

Returns:

second component of the inclination vector

getIx

public double getIx()

Get the first component of the inclination vector.

Returns:

sin(i/2) cos(Ω), first component of the inclination vector

getIy

public double getIy()

Get the second component of the inclination vector.

Returns:

sin(i/2) sin(Ω), second component of the inclination vector

getLE

public double getLE()

Get the eccentric longitude argument.

Not implemented yet.

Specified by:

getLE in class Orbit

Returns:

eccentric longitude argument (rad)

getLv

public double getLv()

Get the true longitude argument.

Not implemented yet.

Specified by:

getLv in class Orbit

Returns:

true longitude argument (rad)

getLM

public double getLM()

Get the mean longitude argument.

Specified by:

getLM in class Orbit

Returns:

M + ω + Ω mean longitude argument (rad)

getE

public double getE()

Get the eccentricity.

Specified by:

getE in class Orbit

Returns:

eccentricity

getI

public double getI()

Get the inclination.

Specified by:

getI in class Orbit

Returns:

inclination (rad)

getN

public double getN()

Get the mean motion.

Specified by:

getN in class Orbit

Returns:

mean motion (1/s)

initPVCoordinates

protected PVCoordinates initPVCoordinates()

Compute the position/velocity coordinates from the canonical parameters.

Specified by:

initPVCoordinates in class Orbit

Returns:

computed position/velocity coordinates

orbitShiftedBy

protected Orbit orbitShiftedBy(double dt)

Get a time-shifted orbit.

The orbit can be slightly shifted to close dates. This shift is based on a simple keplerian model. It is not intended as a replacement for proper orbit and attitude propagation but should be sufficient for small time shifts or coarse accuracy.

Specified by:

orbitShiftedBy in class Orbit

Parameters:

dt - time shift in seconds

Returns:

a new orbit, shifted with respect to the instance (which is immutable)

getPVCoordinates

public PVCoordinates getPVCoordinates(AbsoluteDate otherDate,
                                      Frame otherFrame)
                               throws PatriusException

Get the PVCoordinates of the body in the selected frame.

Specified by:

getPVCoordinates in interface PVCoordinatesProvider

Overrides:

getPVCoordinates in class Orbit

Parameters:

otherDate - current date

otherFrame - the frame where to define the position

Returns:

position/velocity of the body (m and m/s)

Throws:

PatriusException - if position cannot be computed in given frame

computeJacobianMeanWrtCartesian

protected double[][] computeJacobianMeanWrtCartesian()

Compute the Jacobian of the orbital parameters with mean angle with respect to the Cartesian parameters.

Element jacobian[i][j] is the derivative of parameter i of the orbit with respect to Cartesian coordinate j. This means each row correspond to one orbital parameter whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.

Specified by:

computeJacobianMeanWrtCartesian in class Orbit

Returns:

6x6 Jacobian matrix

See Also:

Orbit.computeJacobianEccentricWrtCartesian(), Orbit.computeJacobianTrueWrtCartesian()

computeJacobianEccentricWrtCartesian

protected double[][] computeJacobianEccentricWrtCartesian()

Compute the Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian parameters.

Element jacobian[i][j] is the derivative of parameter i of the orbit with respect to Cartesian coordinate j. This means each row correspond to one orbital parameter whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.

Not implemented yet.

Specified by:

computeJacobianEccentricWrtCartesian in class Orbit

Returns:

6x6 Jacobian matrix

See Also:

Orbit.computeJacobianMeanWrtCartesian(), Orbit.computeJacobianTrueWrtCartesian()

computeJacobianTrueWrtCartesian

protected double[][] computeJacobianTrueWrtCartesian()

Compute the Jacobian of the orbital parameters with true angle with respect to the Cartesian parameters.

Element jacobian[i][j] is the derivative of parameter i of the orbit with respect to Cartesian coordinate j. This means each row correspond to one orbital parameter whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.

Not implemented yet.

Specified by:

computeJacobianTrueWrtCartesian in class Orbit

Returns:

6x6 Jacobian matrix

See Also:

Orbit.computeJacobianMeanWrtCartesian(), Orbit.computeJacobianEccentricWrtCartesian()

orbitAddKeplerContribution

protected void orbitAddKeplerContribution(PositionAngle type,
                                          double gm,
                                          double[] pDot)

Add the contribution of the Keplerian motion to parameters derivatives

This method is used by numerical propagators to evaluate the part of Keplerrian motion to evolution of the orbital state.

Parameters:

type - type of the position angle in the state

gm - attraction coefficient to use

pDot - array containing orbital state derivatives to update (the Keplerian part must be added to the array components, as the array may already contain some non-zero elements corresponding to non-Keplerian parts)

addKeplerContribution

public void addKeplerContribution(PositionAngle type,
                                  double gm,
                                  double[] pDot)

Call the method orbitAddKeplerContribution(PositionAngle, double, double[]) implemented in inherited classes of Orbit.

Parameters:

type - type of the position angle in the state

gm - attraction coefficient to use

pDot - array containing orbital state derivatives to update (the Keplerian part must be added to the array components, as the array may already contain some non-zero elements corresponding to non-Keplerian parts)

mapOrbitToArray

public double[] mapOrbitToArray()

Substitute for Orekit's OrbitTypes.mapOrbitToArray. Warning, unlike other Orekit Orbits lm is returned in second position

Returns:

an array with the following parameters, in this order :

• a
• lm
• ey
• ix
• iy
• ex

kepEq

public double kepEq(double e,
                    double mMod)

Implementation of a Kepler Equation Solver described by F. Landis Markley. (without Pade correction for e>0,75 and E<45deg)

Parameters:

e - eccentricity

mMod - mean anomaly

Returns:

eccentric anomaly in [0;2π]

equals

public boolean equals(Object object)

Test for the equality of two orbits.

Orbits are considered equals if they have the same type and all their attributes are equals. In particular, the orbits frame are considered equals if they represent the same instance. If they have the same attributes but are not the same instance, the method will return false.

Specified by:

equals in class Orbit

Parameters:

object - Object to test for equality to this

Returns:

true if two orbits are equal

hashCode

public int hashCode()

Get a hashCode for the orbit.

Specified by:

hashCode in class Orbit

Returns:

a hash code value for this object