org.orekit.orbits.orbitalparameters
Class EquinoctialParameters

java.lang.Object
  org.orekit.orbits.orbitalparameters.AbstractOrbitalParameters
      org.orekit.orbits.orbitalparameters.EquinoctialParameters

All Implemented Interfaces:

Serializable, IOrbitalParameters

public class EquinoctialParameters
extends AbstractOrbitalParameters

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

The parameters used internally are the equinoctial elements which can be related to keplerian elements as follows:

     a
     ex = e cos(ω + Ω)
     ey = e sin(ω + Ω)
     hx = tan(i/2) cos(Ω)
     hy = tan(i/2) sin(Ω)
     lv = v + ω + Ω
   

where ω stands for the Perigee Argument and Ω stands for the Right Ascension of the Ascending Node.

The conversion equations from and to keplerian elements given above hold only when both sides are unambiguously defined, i.e. when orbit is neither equatorial nor circular. When orbit is either equatorial or circular, the equinoctial parameters are still unambiguously defined whereas some keplerian elements (more precisely ω and Ω) become ambiguous. For this reason, equinoctial parameters are the recommended way to represent orbits.

Since:

3.0

Version:

$Id: EquinoctialParameters.java 14944 2015-12-17 11:03:36Z galpin $

Author:

Emmanuel Bignon

See Also:

Serialized Form

Concurrency :

immutable

Constructor Summary

EquinoctialParameters(double a, double ex, double ey, double hx, double hy, double l, PositionAngle type, double mu)
Creates a new instance.

Method Summary

double	getA() Get the semi-major axis.
ApsisAltitudeParameters	getApsisAltitudeParameters(double ae) Convert current orbital parameters into apsis (using altitude) parameters.
ApsisRadiusParameters	getApsisRadiusParameters() Convert current orbital parameters into apsis (using radius) parameters.
CartesianParameters	getCartesianParameters() Convert current orbital parameters into cartesian parameters.
CircularParameters	getCircularParameters() Convert current orbital parameters into circular parameters.
EquatorialParameters	getEquatorialParameters() Convert current orbital parameters into equatorial parameters.
double	getEquinoctialEx() Get the first component of the eccentricity vector.
double	getEquinoctialEy() Get the second component of the eccentricity vector.
EquinoctialParameters	getEquinoctialParameters() Convert current orbital parameters into equinoctial parameters.
double	getHx() Get the first component of the inclination vector.
double	getHy() Get the second component of the inclination vector.
KeplerianParameters	getKeplerianParameters() Convert current orbital parameters into Keplerian parameters.
double	getL(PositionAngle type) Get the longitude argument.
double	getLE() Get the eccentric longitude argument.
double	getLM() Get the mean longitude argument.
double	getLv() Get the true longitude argument.
ReentryParameters	getReentryParameters(double ae, double f) Convert current orbital parameters into reentry parameters.
StelaEquinoctialParameters	getStelaEquinoctialParameters() Convert current orbital parameters into Stela equinoctial parameters.
String	toString() Returns a string representation of this orbit parameters object.

Methods inherited from class org.orekit.orbits.orbitalparameters.AbstractOrbitalParameters

getMu

Methods inherited from class java.lang.Object

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

Constructor Detail

EquinoctialParameters

public EquinoctialParameters(double a,
                             double ex,
                             double ey,
                             double hx,
                             double hy,
                             double l,
                             PositionAngle type,
                             double mu)
                      throws IllegalArgumentException

Creates a new instance.

Parameters:

a - semi-major axis (m)

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

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

hx - tan(i/2) cos(Ω), first component of inclination vector

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

l - (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)

type - type of longitude argument

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger

Method Detail

getA

public double getA()

Get the semi-major axis.

Returns:

semi-major axis (m)

getEquinoctialEx

public double getEquinoctialEx()

Get the first component of the eccentricity vector.

Returns:

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

getEquinoctialEy

public double getEquinoctialEy()

Get the second component of the eccentricity vector.

Returns:

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

getHx

public double getHx()

Get the first component of the inclination vector.

Returns:

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

getHy

public double getHy()

Get the second component of the inclination vector.

Returns:

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

getL

public double getL(PositionAngle type)

Get the longitude argument.

Parameters:

type - type of the angle

Returns:

longitude argument (rad)

getLv

public double getLv()

Get the true longitude argument.

Returns:

v + ω + Ω true longitude argument (rad)

getLE

public double getLE()

Get the eccentric longitude argument.

Returns:

E + ω + Ω eccentric longitude argument (rad)

getLM

public double getLM()

Get the mean longitude argument.

Returns:

M + ω + Ω mean longitude argument (rad)

getCartesianParameters

public CartesianParameters getCartesianParameters()

Convert current orbital parameters into cartesian parameters.

Returns:

current orbital parameters converted into cartesian parameters

See Also:

CartesianParameters

getKeplerianParameters

public KeplerianParameters getKeplerianParameters()

Convert current orbital parameters into Keplerian parameters.

Returns:

current orbital parameters converted into Keplerian parameters

See Also:

KeplerianParameters

getCircularParameters

public CircularParameters getCircularParameters()

Convert current orbital parameters into circular parameters.

Returns:

current orbital parameters converted into circular parameters

See Also:

CircularParameters

getEquatorialParameters

public EquatorialParameters getEquatorialParameters()

Convert current orbital parameters into equatorial parameters.

Returns:

current orbital parameters converted into equatorial parameters

See Also:

EquatorialParameters

getEquinoctialParameters

public EquinoctialParameters getEquinoctialParameters()

Convert current orbital parameters into equinoctial parameters.

Returns:

current orbital parameters converted into equinoctial parameters

See Also:

EquinoctialParameters

getApsisAltitudeParameters

public ApsisAltitudeParameters getApsisAltitudeParameters(double ae)

Convert current orbital parameters into apsis (using altitude) parameters.

Parameters:

ae - equatorial radius (m)

Returns:

current orbital parameters converted into apsis (using altitude) parameters

See Also:

ApsisAltitudeParameters

getApsisRadiusParameters

public ApsisRadiusParameters getApsisRadiusParameters()

Convert current orbital parameters into apsis (using radius) parameters.

Returns:

current orbital parameters converted into apsis (using radius) parameters

See Also:

ApsisRadiusParameters

getReentryParameters

public ReentryParameters getReentryParameters(double ae,
                                              double f)

Convert current orbital parameters into reentry parameters.

Parameters:

ae - equatorial radius (m)

f - flattening (f = (a-b)/a)

Returns:

current orbital parameters converted into reentry parameters

See Also:

ReentryParameters

getStelaEquinoctialParameters

public StelaEquinoctialParameters getStelaEquinoctialParameters()

Convert current orbital parameters into Stela equinoctial parameters.

Returns:

current orbital parameters converted into Stela equinoctial parameters

See Also:

StelaEquinoctialParameters

toString

public String toString()

Returns a string representation of this orbit parameters object.

Overrides:

toString in class Object

Returns:

a string representation of this object