Class EquinoctialOrbit
- java.lang.Object
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- org.orekit.orbits.Orbit
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- org.orekit.orbits.EquinoctialOrbit
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- All Implemented Interfaces:
Serializable
,PositionAngleBased
,TimeShiftable<Orbit>
,TimeStamped
,PVCoordinatesProvider
public class EquinoctialOrbit extends Orbit implements PositionAngleBased
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. Note however than the present implementation does not handle non-elliptical cases.
The instance
EquinoctialOrbit
is guaranteed to be immutable.- Author:
- Mathieu Roméro, Luc Maisonobe, Guylaine Prat, Fabien Maussion, Véronique Pommier-Maurussane
- See Also:
Orbit
,KeplerianOrbit
,CircularOrbit
,CartesianOrbit
, Serialized Form
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Constructor Summary
Constructors Constructor Description EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, double aDot, double exDot, double eyDot, double hxDot, double hyDot, double lDot, PositionAngleType type, Frame frame, AbsoluteDate date, double mu)
Creates a new instance with derivatives and with cached position angle same as value inputted.EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, double aDot, double exDot, double eyDot, double hxDot, double hyDot, double lDot, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu)
Creates a new instance.EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, PositionAngleType type, Frame frame, AbsoluteDate date, double mu)
Creates a new instance without derivatives and with cached position angle same as value inputted.EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu)
Creates a new instance.EquinoctialOrbit(Orbit op)
Constructor from any kind of orbital parameters.EquinoctialOrbit(PVCoordinates pvCoordinates, Frame frame, AbsoluteDate date, double mu)
Constructor from Cartesian parameters.EquinoctialOrbit(TimeStampedPVCoordinates pvCoordinates, Frame frame, double mu)
Constructor from Cartesian parameters.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods Modifier and Type Method Description void
addKeplerContribution(PositionAngleType type, double gm, double[] pDot)
Add the contribution of the Keplerian motion to parameters derivativesprotected 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.static double
eccentricToMean(double lE, double ex, double ey)
Deprecated.static double
eccentricToTrue(double lE, double ex, double ey)
Deprecated.double
getA()
Get the semi-major axis.double
getADot()
Get the semi-major axis derivative.PositionAngleType
getCachedPositionAngleType()
Get the cachedPositionAngleType
.double
getE()
Get the eccentricity.double
getEDot()
Get the eccentricity derivative.double
getEquinoctialEx()
Get the first component of the equinoctial eccentricity vector.double
getEquinoctialExDot()
Get the first component of the equinoctial eccentricity vector derivative.double
getEquinoctialEy()
Get the second component of the equinoctial eccentricity vector.double
getEquinoctialEyDot()
Get the second component of the equinoctial eccentricity vector derivative.double
getHx()
Get the first component of the inclination vector.double
getHxDot()
Get the first component of the inclination vector derivative.double
getHy()
Get the second component of the inclination vector.double
getHyDot()
Get the second component of the inclination vector derivative.double
getI()
Get the inclination.double
getIDot()
Get the inclination derivative.double
getL(PositionAngleType type)
Get the longitude argument.double
getLDot(PositionAngleType type)
Get the longitude argument derivative.double
getLE()
Get the eccentric longitude argument.double
getLEDot()
Get the eccentric longitude argument derivative.double
getLM()
Get the mean longitude argument.double
getLMDot()
Get the mean longitude argument derivative.double
getLv()
Get the true longitude argument.double
getLvDot()
Get the true longitude argument derivative.OrbitType
getType()
Get the orbit type.boolean
hasRates()
Tells whether the instance holds rates (first-order time derivatives) for dependent variables.protected Vector3D
initPosition()
Compute the position coordinates from the canonical parameters.protected TimeStampedPVCoordinates
initPVCoordinates()
Compute the position/velocity coordinates from the canonical parameters.static double
meanToEccentric(double lM, double ex, double ey)
Deprecated.EquinoctialOrbit
removeRates()
Create a new instance such thatPositionAngleBased.hasRates()
is false.EquinoctialOrbit
shiftedBy(double dt)
Get a time-shifted orbit.String
toString()
Returns a string representation of this equinoctial parameters object.static double
trueToEccentric(double lv, double ex, double ey)
Deprecated.-
Methods inherited from class org.orekit.orbits.Orbit
fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, getDate, getFrame, getJacobianWrtCartesian, getJacobianWrtParameters, getKeplerianMeanMotion, getKeplerianPeriod, getMeanAnomalyDotWrtA, getMu, getPosition, getPosition, getPosition, getPVCoordinates, getPVCoordinates, getPVCoordinates, hasDerivatives, hasNonKeplerianAcceleration, isElliptical
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Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
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Methods inherited from interface org.orekit.time.TimeStamped
durationFrom
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Constructor Detail
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EquinoctialOrbit
public EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
Creates a new instance.- Parameters:
a
- semi-major axis (m)ex
- e cos(ω + Ω), first component of eccentricity vectorey
- e sin(ω + Ω), second component of eccentricity vectorhx
- tan(i/2) cos(Ω), first component of inclination vectorhy
- tan(i/2) sin(Ω), second component of inclination vectorl
- (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)type
- type of longitude argumentcachedPositionAngleType
- type of cached longitude argumentframe
- the frame in which the parameters are defined (must be apseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
- Since:
- 12.1
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EquinoctialOrbit
public EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, PositionAngleType type, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
Creates a new instance without derivatives and with cached position angle same as value inputted.- Parameters:
a
- semi-major axis (m)ex
- e cos(ω + Ω), first component of eccentricity vectorey
- e sin(ω + Ω), second component of eccentricity vectorhx
- tan(i/2) cos(Ω), first component of inclination vectorhy
- tan(i/2) sin(Ω), second component of inclination vectorl
- (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)type
- type of longitude argumentframe
- the frame in which the parameters are defined (must be apseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
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EquinoctialOrbit
public EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, double aDot, double exDot, double eyDot, double hxDot, double hyDot, double lDot, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
Creates a new instance.- Parameters:
a
- semi-major axis (m)ex
- e cos(ω + Ω), first component of eccentricity vectorey
- e sin(ω + Ω), second component of eccentricity vectorhx
- tan(i/2) cos(Ω), first component of inclination vectorhy
- tan(i/2) sin(Ω), second component of inclination vectorl
- (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)aDot
- semi-major axis derivative (m/s)exDot
- d(e cos(ω + Ω))/dt, first component of eccentricity vector derivativeeyDot
- d(e sin(ω + Ω))/dt, second component of eccentricity vector derivativehxDot
- d(tan(i/2) cos(Ω))/dt, first component of inclination vector derivativehyDot
- d(tan(i/2) sin(Ω))/dt, second component of inclination vector derivativelDot
- d(M or E or v) + ω + Ω)/dr, mean, eccentric or true longitude argument derivative (rad/s)type
- type of longitude argumentcachedPositionAngleType
- of cached longitude argumentframe
- the frame in which the parameters are defined (must be apseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
- Since:
- 12.1
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EquinoctialOrbit
public EquinoctialOrbit(double a, double ex, double ey, double hx, double hy, double l, double aDot, double exDot, double eyDot, double hxDot, double hyDot, double lDot, PositionAngleType type, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
Creates a new instance with derivatives and with cached position angle same as value inputted.- Parameters:
a
- semi-major axis (m)ex
- e cos(ω + Ω), first component of eccentricity vectorey
- e sin(ω + Ω), second component of eccentricity vectorhx
- tan(i/2) cos(Ω), first component of inclination vectorhy
- tan(i/2) sin(Ω), second component of inclination vectorl
- (M or E or v) + ω + Ω, mean, eccentric or true longitude argument (rad)aDot
- semi-major axis derivative (m/s)exDot
- d(e cos(ω + Ω))/dt, first component of eccentricity vector derivativeeyDot
- d(e sin(ω + Ω))/dt, second component of eccentricity vector derivativehxDot
- d(tan(i/2) cos(Ω))/dt, first component of inclination vector derivativehyDot
- d(tan(i/2) sin(Ω))/dt, second component of inclination vector derivativelDot
- d(M or E or v) + ω + Ω)/dr, mean, eccentric or true longitude argument derivative (rad/s)type
- type of longitude argumentframe
- the frame in which the parameters are defined (must be apseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
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EquinoctialOrbit
public EquinoctialOrbit(TimeStampedPVCoordinates pvCoordinates, Frame frame, double mu) throws IllegalArgumentException
Constructor from Cartesian parameters.The acceleration provided in
pvCoordinates
is accessible usingOrbit.getPVCoordinates()
andOrbit.getPVCoordinates(Frame)
. All other methods usemu
and the position to compute the acceleration, includingshiftedBy(double)
andOrbit.getPVCoordinates(AbsoluteDate, Frame)
.- Parameters:
pvCoordinates
- the position, velocity and accelerationframe
- the frame in which are defined thePVCoordinates
(must be apseudo-inertial frame
)mu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
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EquinoctialOrbit
public EquinoctialOrbit(PVCoordinates pvCoordinates, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
Constructor from Cartesian parameters.The acceleration provided in
pvCoordinates
is accessible usingOrbit.getPVCoordinates()
andOrbit.getPVCoordinates(Frame)
. All other methods usemu
and the position to compute the acceleration, includingshiftedBy(double)
andOrbit.getPVCoordinates(AbsoluteDate, Frame)
.- Parameters:
pvCoordinates
- the position end velocityframe
- the frame in which are defined thePVCoordinates
(must be apseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)- Throws:
IllegalArgumentException
- if eccentricity is equal to 1 or larger or if frame is not apseudo-inertial frame
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EquinoctialOrbit
public EquinoctialOrbit(Orbit op)
Constructor from any kind of orbital parameters.- Parameters:
op
- orbital parameters to copy
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Method Detail
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getType
public OrbitType getType()
Get the orbit type.
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getA
public double getA()
Get the semi-major axis.Note that the semi-major axis is considered negative for hyperbolic orbits.
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getADot
public double getADot()
Get the semi-major axis derivative.Note that the semi-major axis is considered negative for hyperbolic orbits.
If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getADot
in classOrbit
- Returns:
- semi-major axis derivative (m/s)
- See Also:
Orbit.hasDerivatives()
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getEquinoctialEx
public double getEquinoctialEx()
Get the first component of the equinoctial eccentricity vector.- Specified by:
getEquinoctialEx
in classOrbit
- Returns:
- first component of the equinoctial eccentricity vector
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getEquinoctialExDot
public double getEquinoctialExDot()
Get the first component of the equinoctial eccentricity vector derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getEquinoctialExDot
in classOrbit
- Returns:
- first component of the equinoctial eccentricity vector derivative
- See Also:
Orbit.hasDerivatives()
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getEquinoctialEy
public double getEquinoctialEy()
Get the second component of the equinoctial eccentricity vector.- Specified by:
getEquinoctialEy
in classOrbit
- Returns:
- second component of the equinoctial eccentricity vector
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getEquinoctialEyDot
public double getEquinoctialEyDot()
Get the second component of the equinoctial eccentricity vector derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getEquinoctialEyDot
in classOrbit
- Returns:
- second component of the equinoctial eccentricity vector derivative
- See Also:
Orbit.hasDerivatives()
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getHx
public double getHx()
Get the first component of the inclination vector.
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getHxDot
public double getHxDot()
Get the first component of the inclination vector derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getHxDot
in classOrbit
- Returns:
- first component of the inclination vector derivative
- See Also:
Orbit.hasDerivatives()
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getHy
public double getHy()
Get the second component of the inclination vector.
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getHyDot
public double getHyDot()
Get the second component of the inclination vector derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getHyDot
in classOrbit
- Returns:
- second component of the inclination vector derivative
- See Also:
Orbit.hasDerivatives()
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getLv
public double getLv()
Get the true longitude argument.
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getLvDot
public double getLvDot()
Get the true longitude argument derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getLvDot
in classOrbit
- Returns:
- d(v + ω + Ω)/dt true longitude argument derivative (rad/s)
- See Also:
Orbit.hasDerivatives()
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getLE
public double getLE()
Get the eccentric longitude argument.
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getLEDot
public double getLEDot()
Get the eccentric longitude argument derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getLEDot
in classOrbit
- Returns:
- d(E + ω + Ω)/dt eccentric longitude argument derivative (rad/s)
- See Also:
Orbit.hasDerivatives()
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getLM
public double getLM()
Get the mean longitude argument.
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getLMDot
public double getLMDot()
Get the mean longitude argument derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getLMDot
in classOrbit
- Returns:
- d(M + ω + Ω)/dt mean longitude argument derivative (rad/s)
- See Also:
Orbit.hasDerivatives()
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getL
public double getL(PositionAngleType type)
Get the longitude argument.- Parameters:
type
- type of the angle- Returns:
- longitude argument (rad)
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getLDot
public double getLDot(PositionAngleType type)
Get the longitude argument derivative.- Parameters:
type
- type of the angle- Returns:
- longitude argument derivative (rad/s)
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eccentricToTrue
@Deprecated public static double eccentricToTrue(double lE, double ex, double ey)
Deprecated.Computes the true longitude argument from the eccentric longitude argument.- Parameters:
lE
- = E + ω + Ω eccentric longitude argument (rad)ex
- first component of the eccentricity vectorey
- second component of the eccentricity vector- Returns:
- the true longitude argument
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trueToEccentric
@Deprecated public static double trueToEccentric(double lv, double ex, double ey)
Deprecated.Computes the eccentric longitude argument from the true longitude argument.- Parameters:
lv
- = v + ω + Ω true longitude argument (rad)ex
- first component of the eccentricity vectorey
- second component of the eccentricity vector- Returns:
- the eccentric longitude argument
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meanToEccentric
@Deprecated public static double meanToEccentric(double lM, double ex, double ey)
Deprecated.Computes the eccentric longitude argument from the mean longitude argument.- Parameters:
lM
- = M + ω + Ω mean longitude argument (rad)ex
- first component of the eccentricity vectorey
- second component of the eccentricity vector- Returns:
- the eccentric longitude argument
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eccentricToMean
@Deprecated public static double eccentricToMean(double lE, double ex, double ey)
Deprecated.Computes the mean longitude argument from the eccentric longitude argument.- Parameters:
lE
- = E + ω + Ω mean longitude argument (rad)ex
- first component of the eccentricity vectorey
- second component of the eccentricity vector- Returns:
- the mean longitude argument
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getE
public double getE()
Get the eccentricity.
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getEDot
public double getEDot()
Get the eccentricity derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getEDot
in classOrbit
- Returns:
- eccentricity derivative
- See Also:
Orbit.hasDerivatives()
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getI
public double getI()
Get the inclination.
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getIDot
public double getIDot()
Get the inclination derivative.If the orbit was created without derivatives, the value returned is
Double.NaN
.- Specified by:
getIDot
in classOrbit
- Returns:
- inclination derivative (rad/s)
- See Also:
Orbit.hasDerivatives()
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initPosition
protected Vector3D initPosition()
Compute the position coordinates from the canonical parameters.- Specified by:
initPosition
in classOrbit
- Returns:
- computed position coordinates
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initPVCoordinates
protected TimeStampedPVCoordinates initPVCoordinates()
Compute the position/velocity coordinates from the canonical parameters.- Specified by:
initPVCoordinates
in classOrbit
- Returns:
- computed position/velocity coordinates
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shiftedBy
public EquinoctialOrbit shiftedBy(double dt)
Get a time-shifted orbit.The orbit can be slightly shifted to close dates. The shifting model is a Keplerian one if no derivatives are available in the orbit, or Keplerian plus quadratic effect of the non-Keplerian acceleration if derivatives are available. Shifting is not intended as a replacement for proper orbit propagation but should be sufficient for small time shifts or coarse accuracy.
- Specified by:
shiftedBy
in interfaceTimeShiftable<Orbit>
- Specified by:
shiftedBy
in classOrbit
- Parameters:
dt
- time shift in seconds- Returns:
- a new orbit, shifted with respect to the instance (which is immutable)
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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.The array returned by this method will not be modified.
- Specified by:
computeJacobianMeanWrtCartesian
in classOrbit
- Returns:
- 6x6 Jacobian matrix
- See Also:
Orbit.computeJacobianEccentricWrtCartesian()
,Orbit.computeJacobianTrueWrtCartesian()
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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.The array returned by this method will not be modified.
- Specified by:
computeJacobianEccentricWrtCartesian
in classOrbit
- Returns:
- 6x6 Jacobian matrix
- See Also:
Orbit.computeJacobianMeanWrtCartesian()
,Orbit.computeJacobianTrueWrtCartesian()
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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.The array returned by this method will not be modified.
- Specified by:
computeJacobianTrueWrtCartesian
in classOrbit
- Returns:
- 6x6 Jacobian matrix
- See Also:
Orbit.computeJacobianMeanWrtCartesian()
,Orbit.computeJacobianEccentricWrtCartesian()
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addKeplerContribution
public void addKeplerContribution(PositionAngleType type, double gm, double[] pDot)
Add the contribution of the Keplerian motion to parameters derivativesThis method is used by integration-based propagators to evaluate the part of Keplerian motion to evolution of the orbital state.
- Specified by:
addKeplerContribution
in classOrbit
- Parameters:
type
- type of the position angle in the stategm
- attraction coefficient to usepDot
- 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)
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toString
public String toString()
Returns a string representation of this equinoctial parameters object.
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getCachedPositionAngleType
public PositionAngleType getCachedPositionAngleType()
Get the cachedPositionAngleType
.- Specified by:
getCachedPositionAngleType
in interfacePositionAngleBased
- Returns:
- cached type of position angle
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hasRates
public boolean hasRates()
Tells whether the instance holds rates (first-order time derivatives) for dependent variables.- Specified by:
hasRates
in interfacePositionAngleBased
- Returns:
- true if and only if holding rates
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removeRates
public EquinoctialOrbit removeRates()
Create a new instance such thatPositionAngleBased.hasRates()
is false.- Specified by:
removeRates
in interfacePositionAngleBased
- Returns:
- new object without rates
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