Package org.orekit.orbits

Class CircularOrbit

java.lang.Object

org.orekit.orbits.Orbit

org.orekit.orbits.CircularOrbit

All Implemented Interfaces:

PositionAngleBased<CircularOrbit>, TimeShiftable<ShiftablePVCoordinatesHolder<Orbit>>, TimeStamped, PVCoordinatesProvider, ShiftablePVCoordinatesHolder<Orbit>

public class CircularOrbit
extends Orbit
implements PositionAngleBased<CircularOrbit>

This class handles circular orbital parameters.

The parameters used internally are the circular elements which can be related to Keplerian elements as follows:

• a
• e_x = e cos(ω)
• e_y = e sin(ω)
• i
• Ω
• α_v = v + ω

where Ω stands for the Right Ascension of the Ascending Node and α_v stands for the true latitude argument

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 circular (but not equatorial), the circular parameters are still unambiguously defined whereas some Keplerian elements (more precisely ω and Ω) become ambiguous. When orbit is equatorial, neither the Keplerian nor the circular parameters can be defined unambiguously. equinoctial orbits is the recommended way to represent orbits.

The instance CircularOrbit is guaranteed to be immutable.

Author:

Luc Maisonobe, Fabien Maussion, Véronique Pommier-Maurussane

See Also:

• Orbit
• KeplerianOrbit
• CartesianOrbit
• EquinoctialOrbit

Field Summary

Fields inherited from class org.orekit.orbits.Orbit

TOLERANCE_POSITION_ANGLE_RATE

Constructor Summary

Constructors

Constructor	Description
CircularOrbit(double a, double ex, double ey, double i, double raan, double alpha, double aDot, double exDot, double eyDot, double iDot, double raanDot, double alphaDot, PositionAngleType type, Frame frame, AbsoluteDate date, double mu)	Creates a new instance with derivatives and with cached position angle same as value inputted.
CircularOrbit(double a, double ex, double ey, double i, double raan, double alpha, double aDot, double exDot, double eyDot, double iDot, double raanDot, double alphaDot, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu)	Creates a new instance.
CircularOrbit(double a, double ex, double ey, double i, double raan, double alpha, PositionAngleType type, Frame frame, AbsoluteDate date, double mu)	Creates a new instance without derivatives and with cached position angle same as value inputted.
CircularOrbit(double a, double ex, double ey, double i, double raan, double alpha, PositionAngleType type, PositionAngleType cachedPositionAngleType, Frame frame, AbsoluteDate date, double mu)	Creates a new instance.
CircularOrbit(Orbit op)	Constructor from any kind of orbital parameters.
CircularOrbit(PVCoordinates pvCoordinates, Frame frame, AbsoluteDate date, double mu)	Constructor from Cartesian parameters.
CircularOrbit(TimeStampedPVCoordinates pvCoordinates, Frame frame, double mu)	Constructor from Cartesian parameters.

Method Summary

Modifier and Type	Method	Description
void	addKeplerContribution(PositionAngleType type, double gm, double[] pDot)	Add the contribution of the Keplerian motion to parameters derivatives
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.
double	getA()	Get the semi-major axis.
double	getADot()	Get the semi-major axis derivative.
double	getAlpha(PositionAngleType type)	Get the latitude argument.
double	getAlphaDot(PositionAngleType type)	Get the latitude argument derivative.
double	getAlphaE()	Get the eccentric latitude argument.
double	getAlphaEDot()	Get the eccentric latitude argument derivative.
double	getAlphaM()	Get the mean latitude argument.
double	getAlphaMDot()	Get the mean latitude argument derivative.
double	getAlphaV()	Get the true latitude argument.
double	getAlphaVDot()	Get the true latitude argument derivative.
PositionAngleType	getCachedPositionAngleType()	Get the cached PositionAngleType.
double	getCircularEx()	Get the first component of the circular eccentricity vector.
double	getCircularExDot()	Get the first component of the circular eccentricity vector derivative.
double	getCircularEy()	Get the second component of the circular eccentricity vector.
double	getCircularEyDot()	Get the second component of the circular eccentricity vector derivative.
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	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.
double	getRightAscensionOfAscendingNode()	Get the right ascension of the ascending node.
double	getRightAscensionOfAscendingNodeDot()	Get the right ascension of the ascending node derivative.
OrbitType	getType()	Get the orbit type.
boolean	hasNonKeplerianAcceleration()	Check if orbit includes non-Keplerian rates.
boolean	hasNonKeplerianRates()	Tells whether the instance holds rates (first-order time derivatives) for dependent variables that are incompatible with Keplerian motion.
CircularOrbit	inFrame(Frame inertialFrame)	Create a new object representing the same physical orbital state, but attached to a different reference frame.
protected Vector3D	initPosition()	Compute the position coordinates from the canonical parameters.
protected TimeStampedPVCoordinates	initPVCoordinates()	Compute the position/velocity coordinates from the canonical parameters.
CircularOrbit	shiftedBy(double dt)	Get a time-shifted orbit.
CircularOrbit	shiftedBy(TimeOffset dt)	Get a time-shifted orbit.
String	toString()	Returns a string representation of this Orbit object.
CircularOrbit	withCachedPositionAngleType(PositionAngleType positionAngleType)	Creates a new instance with the provided type used for caching.
CircularOrbit	withKeplerianRates()	Creates a new instance such that PositionAngleBased.hasNonKeplerianRates() is false.

Methods inherited from class org.orekit.orbits.Orbit

fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, getDate, getDecompositionSolver, getFrame, getJacobianWrtCartesian, getJacobianWrtParameters, getKeplerianMeanMotion, getKeplerianPeriod, getMeanAnomalyDotWrtA, getMu, getPosition, getPVCoordinates, hasNonKeplerianAcceleration, isElliptical, nonKeplerianAcceleration, shiftNonKeplerian

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.utils.ShiftablePVCoordinatesHolder

getPosition, getPosition, getPVCoordinates, getPVCoordinates, getVelocity, getVelocity, getVelocity

Methods inherited from interface org.orekit.time.TimeStamped

durationFrom

Constructor Details

CircularOrbit

public CircularOrbit(double a,
 double ex,
 double ey,
 double i,
 double raan,
 double alpha,
 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), first component of circular eccentricity vector

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

i - inclination (rad)

raan - right ascension of ascending node (Ω, rad)

alpha - an + ω, mean, eccentric or true latitude argument (rad)

type - type of latitude argument

cachedPositionAngleType - type of cached latitude argument

frame - the frame in which are defined the parameters (must be a pseudo-inertial frame)

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame

Since:

12.1

CircularOrbit

public CircularOrbit(double a,
 double ex,
 double ey,
 double i,
 double raan,
 double alpha,
 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), first component of circular eccentricity vector

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

i - inclination (rad)

raan - right ascension of ascending node (Ω, rad)

alpha - an + ω, mean, eccentric or true latitude argument (rad)

type - type of latitude argument

frame - the frame in which are defined the parameters (must be a pseudo-inertial frame)

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame

CircularOrbit

public CircularOrbit(double a,
 double ex,
 double ey,
 double i,
 double raan,
 double alpha,
 double aDot,
 double exDot,
 double eyDot,
 double iDot,
 double raanDot,
 double alphaDot,
 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), first component of circular eccentricity vector

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

i - inclination (rad)

raan - right ascension of ascending node (Ω, rad)

alpha - an + ω, mean, eccentric or true latitude argument (rad)

aDot - semi-major axis derivative (m/s)

exDot - d(e cos(ω))/dt, first component of circular eccentricity vector derivative

eyDot - d(e sin(ω))/dt, second component of circular eccentricity vector derivative

iDot - inclination derivative(rad/s)

raanDot - right ascension of ascending node derivative (rad/s)

alphaDot - d(an + ω), mean, eccentric or true latitude argument derivative (rad/s)

type - type of latitude argument

cachedPositionAngleType - type of cached latitude argument

frame - the frame in which are defined the parameters (must be a pseudo-inertial frame)

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame

Since:

12.1

CircularOrbit

public CircularOrbit(double a,
 double ex,
 double ey,
 double i,
 double raan,
 double alpha,
 double aDot,
 double exDot,
 double eyDot,
 double iDot,
 double raanDot,
 double alphaDot,
 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), first component of circular eccentricity vector

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

i - inclination (rad)

raan - right ascension of ascending node (Ω, rad)

alpha - an + ω, mean, eccentric or true latitude argument (rad)

aDot - semi-major axis derivative (m/s)

exDot - d(e cos(ω))/dt, first component of circular eccentricity vector derivative

eyDot - d(e sin(ω))/dt, second component of circular eccentricity vector derivative

iDot - inclination derivative(rad/s)

raanDot - right ascension of ascending node derivative (rad/s)

alphaDot - d(an + ω), mean, eccentric or true latitude argument derivative (rad/s)

type - type of latitude argument

frame - the frame in which are defined the parameters (must be a pseudo-inertial frame)

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if eccentricity is equal to 1 or larger or if frame is not a pseudo-inertial frame

CircularOrbit

public CircularOrbit(TimeStampedPVCoordinates pvCoordinates,
 Frame frame,
 double mu)
              throws IllegalArgumentException

Constructor from Cartesian parameters.

The acceleration provided in pvCoordinates is accessible using Orbit.getPVCoordinates() and ShiftablePVCoordinatesHolder.getPVCoordinates(Frame). All other methods use mu and the position to compute the acceleration, including shiftedBy(double) and ShiftablePVCoordinatesHolder.getPVCoordinates(AbsoluteDate, Frame).

Parameters:

pvCoordinates - the PVCoordinates in inertial frame

frame - the frame in which are defined the PVCoordinates (must be a pseudo-inertial frame)

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if frame is not a pseudo-inertial frame

CircularOrbit

public CircularOrbit(PVCoordinates pvCoordinates,
 Frame frame,
 AbsoluteDate date,
 double mu)
              throws IllegalArgumentException

Constructor from Cartesian parameters.

The acceleration provided in pvCoordinates is accessible using Orbit.getPVCoordinates() and ShiftablePVCoordinatesHolder.getPVCoordinates(Frame). All other methods use mu and the position to compute the acceleration, including shiftedBy(double) and ShiftablePVCoordinatesHolder.getPVCoordinates(AbsoluteDate, Frame).

Parameters:

pvCoordinates - the PVCoordinates in inertial frame

frame - the frame in which are defined the PVCoordinates (must be a pseudo-inertial frame)

date - date of the orbital parameters

mu - central attraction coefficient (m³/s²)

Throws:

IllegalArgumentException - if frame is not a pseudo-inertial frame

CircularOrbit

public CircularOrbit(Orbit op)

Constructor from any kind of orbital parameters.

Parameters:

op - orbital parameters to copy

Method Details

hasNonKeplerianAcceleration

public boolean hasNonKeplerianAcceleration()

Check if orbit includes non-Keplerian rates.

Overrides:

hasNonKeplerianAcceleration in class Orbit

Returns:

true if orbit includes non-Keplerian derivatives

See Also:

• Orbit.getADot()
• Orbit.getEquinoctialExDot()
• Orbit.getEquinoctialEyDot()
• Orbit.getHxDot()
• Orbit.getHyDot()
• Orbit.getLEDot()
• Orbit.getLvDot()
• Orbit.getLMDot()
• Orbit.getEDot()
• Orbit.getIDot()

getType

public OrbitType getType()

Get the orbit type.

Specified by:

getType in class Orbit

Returns:

orbit type

getA

public double getA()

Get the semi-major axis.

Note that the semi-major axis is considered negative for hyperbolic orbits.

Specified by:

getA in class Orbit

Returns:

semi-major axis (m)

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 class Orbit

Returns:

semi-major axis derivative (m/s)

getEquinoctialEx

public double getEquinoctialEx()

Get the first component of the equinoctial eccentricity vector.

Specified by:

getEquinoctialEx in class Orbit

Returns:

first component of the equinoctial eccentricity vector

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 class Orbit

Returns:

first component of the equinoctial eccentricity vector derivative

getEquinoctialEy

public double getEquinoctialEy()

Get the second component of the equinoctial eccentricity vector.

Specified by:

getEquinoctialEy in class Orbit

Returns:

second component of the equinoctial eccentricity vector

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 class Orbit

Returns:

second component of the equinoctial eccentricity vector derivative

getCircularEx

public double getCircularEx()

Get the first component of the circular eccentricity vector.

Returns:

ex = e cos(ω), first component of the circular eccentricity vector

getCircularExDot

public double getCircularExDot()

Get the first component of the circular eccentricity vector derivative.

Returns:

ex = e cos(ω), first component of the circular eccentricity vector derivative

Since:

9.0

getCircularEy

public double getCircularEy()

Get the second component of the circular eccentricity vector.

Returns:

ey = e sin(ω), second component of the circular eccentricity vector

getCircularEyDot

public double getCircularEyDot()

Get the second component of the circular eccentricity vector derivative.

Returns:

ey = e sin(ω), second component of the circular eccentricity vector derivative

getHx

public double getHx()

Get the first component of the inclination vector.

Specified by:

getHx in class Orbit

Returns:

first component of the inclination vector

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 class Orbit

Returns:

first component of the inclination vector derivative

getHy

public double getHy()

Get the second component of the inclination vector.

Specified by:

getHy in class Orbit

Returns:

second component of the inclination vector

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 class Orbit

Returns:

second component of the inclination vector derivative

getAlphaV

public double getAlphaV()

Get the true latitude argument.

Returns:

v + ω true latitude argument (rad)

getAlphaVDot

public double getAlphaVDot()

Get the true latitude argument derivative.

If the orbit was created without derivatives, the value returned is Double.NaN.

Returns:

v + ω true latitude argument derivative (rad/s)

Since:

9.0

getAlphaE

public double getAlphaE()

Get the eccentric latitude argument.

Returns:

E + ω eccentric latitude argument (rad)

getAlphaEDot

public double getAlphaEDot()

Get the eccentric latitude argument derivative.

If the orbit was created without derivatives, the value returned is Double.NaN.

Returns:

d(E + ω)/dt eccentric latitude argument derivative (rad/s)

Since:

9.0

getAlphaM

public double getAlphaM()

Get the mean latitude argument.

Returns:

M + ω mean latitude argument (rad)

getAlphaMDot

public double getAlphaMDot()

Get the mean latitude argument derivative.

If the orbit was created without derivatives, the value returned is Double.NaN.

Returns:

d(M + ω)/dt mean latitude argument derivative (rad/s)

Since:

9.0

getAlpha

public double getAlpha(PositionAngleType type)

Get the latitude argument.

Parameters:

type - type of the angle

Returns:

latitude argument (rad)

getAlphaDot

public double getAlphaDot(PositionAngleType type)

Get the latitude argument derivative.

If the orbit was created without derivatives, the value returned is Double.NaN.

Parameters:

type - type of the angle

Returns:

latitude argument derivative (rad/s)

Since:

9.0

getE

public double getE()

Get the eccentricity.

Specified by:

getE in class Orbit

Returns:

eccentricity

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 class Orbit

Returns:

eccentricity derivative

getI

public double getI()

Get the inclination.

Specified by:

getI in class Orbit

Returns:

inclination (rad)

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 class Orbit

Returns:

inclination derivative (rad/s)

getRightAscensionOfAscendingNode

public double getRightAscensionOfAscendingNode()

Get the right ascension of the ascending node.

Returns:

right ascension of the ascending node (rad)

getRightAscensionOfAscendingNodeDot

public double getRightAscensionOfAscendingNodeDot()

Get the right ascension of the ascending node derivative.

If the orbit was created without derivatives, the value returned is Double.NaN.

Returns:

right ascension of the ascending node derivative (rad/s)

Since:

9.0

getLv

public double getLv()

Get the true longitude argument.

Specified by:

getLv in class Orbit

Returns:

v + ω + Ω true longitude argument (rad)

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 class Orbit

Returns:

d(v + ω + Ω)/dt true longitude argument derivative (rad/s)

getLE

public double getLE()

Get the eccentric longitude argument.

Specified by:

getLE in class Orbit

Returns:

E + ω + Ω eccentric longitude argument (rad)

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 class Orbit

Returns:

d(E + ω + Ω)/dt eccentric longitude argument derivative (rad/s)

getLM

public double getLM()

Get the mean longitude argument.

Specified by:

getLM in class Orbit

Returns:

M + ω + Ω mean longitude argument (rad)

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 class Orbit

Returns:

d(M + ω + Ω)/dt mean longitude argument derivative (rad/s)

initPosition

protected Vector3D initPosition()

Compute the position coordinates from the canonical parameters.

Specified by:

initPosition in class Orbit

Returns:

computed position coordinates

initPVCoordinates

protected TimeStampedPVCoordinates initPVCoordinates()

Compute the position/velocity coordinates from the canonical parameters.

Specified by:

initPVCoordinates in class Orbit

Returns:

computed position/velocity coordinates

inFrame

public CircularOrbit inFrame(Frame inertialFrame)

Create a new object representing the same physical orbital state, but attached to a different reference frame. If the new frame is not inertial, an exception will be thrown.

Specified by:

inFrame in class Orbit

Parameters:

inertialFrame - reference frame of output orbit

Returns:

orbit with different frame

withCachedPositionAngleType

public CircularOrbit withCachedPositionAngleType(PositionAngleType positionAngleType)

Creates a new instance with the provided type used for caching.

Specified by:

withCachedPositionAngleType in interface PositionAngleBased<CircularOrbit>

Parameters:

positionAngleType - position angle type to use for caching value

Returns:

new object

shiftedBy

public CircularOrbit 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 interface TimeShiftable<ShiftablePVCoordinatesHolder<Orbit>>

Specified by:

shiftedBy in class Orbit

Parameters:

dt - time shift in seconds

Returns:

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

shiftedBy

public CircularOrbit shiftedBy(TimeOffset 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 interface TimeShiftable<ShiftablePVCoordinatesHolder<Orbit>>

Specified by:

shiftedBy in class Orbit

Parameters:

dt - time shift

Returns:

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

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 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.

The array returned by this method will not be modified.

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.

The array returned by this method will not be modified.

Specified by:

computeJacobianTrueWrtCartesian in class Orbit

Returns:

6x6 Jacobian matrix

See Also:

• Orbit.computeJacobianMeanWrtCartesian()
• Orbit.computeJacobianEccentricWrtCartesian()

addKeplerContribution

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

Add the contribution of the Keplerian motion to parameters derivatives

This method is used by integration-based propagators to evaluate the part of Keplerian motion to evolution of the orbital state.

Specified by:

addKeplerContribution in class 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)

toString

public String toString()

Returns a string representation of this Orbit object.

Overrides:

toString in class Object

Returns:

a string representation of this object

getCachedPositionAngleType

public PositionAngleType getCachedPositionAngleType()

Get the cached PositionAngleType.

Specified by:

getCachedPositionAngleType in interface PositionAngleBased<CircularOrbit>

Returns:

cached type of position angle

hasNonKeplerianRates

public boolean hasNonKeplerianRates()

Tells whether the instance holds rates (first-order time derivatives) for dependent variables that are incompatible with Keplerian motion.

Specified by:

hasNonKeplerianRates in interface PositionAngleBased<CircularOrbit>

Returns:

true if and only if holding non-Keplerian rates

withKeplerianRates

public CircularOrbit withKeplerianRates()

Creates a new instance such that PositionAngleBased.hasNonKeplerianRates() is false.

Specified by:

withKeplerianRates in interface PositionAngleBased<CircularOrbit>

Returns:

new object without rates