public class KeplerianOrbit extends Orbit
The parameters used internally are the classical Keplerian elements:
a e i ω Ω vwhere ω stands for the Perigee Argument, Ω stands for the Right Ascension of the Ascending Node and v stands for the true anomaly.
This class supports hyperbolic orbits, using the convention that semi major axis is negative for such orbits (and of course eccentricity is greater than 1).
When orbit is either equatorial or circular, some Keplerian elements
(more precisely ω and Ω) become ambiguous so this class should not
be used for such orbits. For this reason, equinoctial
orbits
is the recommended way to represent orbits.
The instance KeplerianOrbit
is guaranteed to be immutable.
Orbit
,
CircularOrbit
,
CartesianOrbit
,
EquinoctialOrbit
,
Serialized FormConstructor and Description |
---|
KeplerianOrbit(double a,
double e,
double i,
double pa,
double raan,
double anomaly,
double aDot,
double eDot,
double iDot,
double paDot,
double raanDot,
double anomalyDot,
PositionAngle type,
Frame frame,
AbsoluteDate date,
double mu)
Creates a new instance.
|
KeplerianOrbit(double a,
double e,
double i,
double pa,
double raan,
double anomaly,
PositionAngle type,
Frame frame,
AbsoluteDate date,
double mu)
Creates a new instance.
|
KeplerianOrbit(Orbit op)
Constructor from any kind of orbital parameters.
|
KeplerianOrbit(PVCoordinates pvCoordinates,
Frame frame,
AbsoluteDate date,
double mu)
Constructor from Cartesian parameters.
|
KeplerianOrbit(TimeStampedPVCoordinates pvCoordinates,
Frame frame,
double mu)
Constructor from Cartesian parameters.
|
Modifier and Type | Method and Description |
---|---|
void |
addKeplerContribution(PositionAngle 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.
|
static double |
ellipticEccentricToMean(double E,
double e)
Computes the mean anomaly from the elliptic eccentric anomaly.
|
static double |
ellipticEccentricToTrue(double E,
double e)
Computes the true anomaly from the elliptic eccentric anomaly.
|
double |
getA()
Get the semi-major axis.
|
double |
getADot()
Get the semi-major axis derivative.
|
double |
getAnomaly(PositionAngle type)
Get the anomaly.
|
double |
getAnomalyDot(PositionAngle type)
Get the anomaly derivative.
|
double |
getE()
Get the eccentricity.
|
double |
getEccentricAnomaly()
Get the eccentric anomaly.
|
double |
getEccentricAnomalyDot()
Get the eccentric anomaly derivative.
|
double |
getEDot()
Get the eccentricity derivative.
|
double |
getEquinoctialEx()
Get the first component of the equinoctial eccentricity vector derivative.
|
double |
getEquinoctialExDot()
Get the first component of the equinoctial eccentricity vector.
|
double |
getEquinoctialEy()
Get the second component of the equinoctial eccentricity vector derivative.
|
double |
getEquinoctialEyDot()
Get the second component of the equinoctial eccentricity vector.
|
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 |
getMeanAnomaly()
Get the mean anomaly.
|
double |
getMeanAnomalyDot()
Get the mean anomaly derivative.
|
double |
getPerigeeArgument()
Get the perigee argument.
|
double |
getPerigeeArgumentDot()
Get the perigee argument derivative.
|
double |
getRightAscensionOfAscendingNode()
Get the right ascension of the ascending node.
|
double |
getRightAscensionOfAscendingNodeDot()
Get the right ascension of the ascending node derivative.
|
double |
getTrueAnomaly()
Get the true anomaly.
|
double |
getTrueAnomalyDot()
Get the true anomaly derivative.
|
OrbitType |
getType()
Get the orbit type.
|
static double |
hyperbolicEccentricToMean(double H,
double e)
Computes the mean anomaly from the hyperbolic eccentric anomaly.
|
static double |
hyperbolicEccentricToTrue(double H,
double e)
Computes the true anomaly from the hyperbolic eccentric anomaly.
|
protected TimeStampedPVCoordinates |
initPVCoordinates()
Compute the position/velocity coordinates from the canonical parameters.
|
KeplerianOrbit |
interpolate(AbsoluteDate date,
Stream<Orbit> sample)
Get an interpolated instance.
|
static double |
meanToEllipticEccentric(double M,
double e)
Computes the elliptic eccentric anomaly from the mean anomaly.
|
static double |
meanToHyperbolicEccentric(double M,
double ecc)
Computes the hyperbolic eccentric anomaly from the mean anomaly.
|
KeplerianOrbit |
shiftedBy(double dt)
Get a time-shifted orbit.
|
String |
toString()
Returns a string representation of this Keplerian parameters object.
|
static double |
trueToEllipticEccentric(double v,
double e)
Computes the elliptic eccentric anomaly from the true anomaly.
|
static double |
trueToHyperbolicEccentric(double v,
double e)
Computes the hyperbolic eccentric anomaly from the true anomaly.
|
fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, fillHalfRow, getDate, getFrame, getJacobianWrtCartesian, getJacobianWrtParameters, getKeplerianMeanMotion, getKeplerianPeriod, getMu, getPVCoordinates, getPVCoordinates, getPVCoordinates, hasDerivatives, hasNonKeplerianAcceleration
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
interpolate
public KeplerianOrbit(double a, double e, double i, double pa, double raan, double anomaly, PositionAngle type, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
a
- semi-major axis (m), negative for hyperbolic orbitse
- eccentricityi
- inclination (rad)pa
- perigee argument (ω, rad)raan
- right ascension of ascending node (Ω, rad)anomaly
- mean, eccentric or true anomaly (rad)type
- type of anomalyframe
- the frame in which the parameters are defined
(must be a pseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)IllegalArgumentException
- if frame is not a pseudo-inertial frame
or a and e don't match for hyperbolic orbits,
or v is out of range for hyperbolic orbitspublic KeplerianOrbit(double a, double e, double i, double pa, double raan, double anomaly, double aDot, double eDot, double iDot, double paDot, double raanDot, double anomalyDot, PositionAngle type, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
a
- semi-major axis (m), negative for hyperbolic orbitse
- eccentricityi
- inclination (rad)pa
- perigee argument (ω, rad)raan
- right ascension of ascending node (Ω, rad)anomaly
- mean, eccentric or true anomaly (rad)aDot
- semi-major axis derivative (m/s)eDot
- eccentricity derivativeiDot
- inclination derivative (rad/s)paDot
- perigee argument derivative (rad/s)raanDot
- right ascension of ascending node derivative (rad/s)anomalyDot
- mean, eccentric or true anomaly derivative (rad/s)type
- type of anomalyframe
- the frame in which the parameters are defined
(must be a pseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)IllegalArgumentException
- if frame is not a pseudo-inertial frame
or a and e don't match for hyperbolic orbits,
or v is out of range for hyperbolic orbitspublic KeplerianOrbit(TimeStampedPVCoordinates pvCoordinates, Frame frame, double mu) throws IllegalArgumentException
The acceleration provided in pvCoordinates
is accessible using
Orbit.getPVCoordinates()
and Orbit.getPVCoordinates(Frame)
. All other methods
use mu
and the position to compute the acceleration, including
shiftedBy(double)
and Orbit.getPVCoordinates(AbsoluteDate, Frame)
.
pvCoordinates
- the PVCoordinates of the satelliteframe
- the frame in which are defined the PVCoordinates
(must be a pseudo-inertial frame
)mu
- central attraction coefficient (m³/s²)IllegalArgumentException
- if frame is not a pseudo-inertial frame
public KeplerianOrbit(PVCoordinates pvCoordinates, Frame frame, AbsoluteDate date, double mu) throws IllegalArgumentException
The acceleration provided in pvCoordinates
is accessible using
Orbit.getPVCoordinates()
and Orbit.getPVCoordinates(Frame)
. All other methods
use mu
and the position to compute the acceleration, including
shiftedBy(double)
and Orbit.getPVCoordinates(AbsoluteDate, Frame)
.
pvCoordinates
- the PVCoordinates of the satelliteframe
- the frame in which are defined the PVCoordinates
(must be a pseudo-inertial frame
)date
- date of the orbital parametersmu
- central attraction coefficient (m³/s²)IllegalArgumentException
- if frame is not a pseudo-inertial frame
public KeplerianOrbit(Orbit op)
op
- orbital parameters to copypublic OrbitType getType()
public double getA()
Note that the semi-major axis is considered negative for hyperbolic orbits.
public double getADot()
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
.
getADot
in class Orbit
Orbit.hasDerivatives()
public double getE()
public double getEDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getEDot
in class Orbit
Orbit.hasDerivatives()
public double getI()
public double getIDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getIDot
in class Orbit
Orbit.hasDerivatives()
public double getPerigeeArgument()
public double getPerigeeArgumentDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
public double getRightAscensionOfAscendingNode()
public double getRightAscensionOfAscendingNodeDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
public double getTrueAnomaly()
public double getTrueAnomalyDot()
public double getEccentricAnomaly()
public double getEccentricAnomalyDot()
public double getMeanAnomaly()
public double getMeanAnomalyDot()
public double getAnomaly(PositionAngle type)
type
- type of the anglepublic double getAnomalyDot(PositionAngle type)
type
- type of the anglepublic static double ellipticEccentricToTrue(double E, double e)
E
- eccentric anomaly (rad)e
- eccentricitypublic static double trueToEllipticEccentric(double v, double e)
v
- true anomaly (rad)e
- eccentricitypublic static double hyperbolicEccentricToTrue(double H, double e)
H
- hyperbolic eccentric anomaly (rad)e
- eccentricitypublic static double trueToHyperbolicEccentric(double v, double e)
v
- true anomaly (rad)e
- eccentricitypublic static double meanToEllipticEccentric(double M, double e)
The algorithm used here for solving Kepler equation has been published in: "Procedures for solving Kepler's Equation", A. W. Odell and R. H. Gooding, Celestial Mechanics 38 (1986) 307-334
M
- mean anomaly (rad)e
- eccentricitypublic static double meanToHyperbolicEccentric(double M, double ecc)
The algorithm used here for solving hyperbolic Kepler equation is Danby's iterative method (3rd order) with Vallado's initial guess.
M
- mean anomaly (rad)ecc
- eccentricitypublic static double ellipticEccentricToMean(double E, double e)
E
- eccentric anomaly (rad)e
- eccentricitypublic static double hyperbolicEccentricToMean(double H, double e)
H
- hyperbolic eccentric anomaly (rad)e
- eccentricitypublic double getEquinoctialEx()
getEquinoctialEx
in class Orbit
public double getEquinoctialExDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getEquinoctialExDot
in class Orbit
Orbit.hasDerivatives()
public double getEquinoctialEy()
getEquinoctialEy
in class Orbit
public double getEquinoctialEyDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getEquinoctialEyDot
in class Orbit
Orbit.hasDerivatives()
public double getHx()
public double getHxDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getHxDot
in class Orbit
Orbit.hasDerivatives()
public double getHy()
public double getHyDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getHyDot
in class Orbit
Orbit.hasDerivatives()
public double getLv()
public double getLvDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getLvDot
in class Orbit
Orbit.hasDerivatives()
public double getLE()
public double getLEDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getLEDot
in class Orbit
Orbit.hasDerivatives()
public double getLM()
public double getLMDot()
If the orbit was created without derivatives, the value returned is Double.NaN
.
getLMDot
in class Orbit
Orbit.hasDerivatives()
protected TimeStampedPVCoordinates initPVCoordinates()
initPVCoordinates
in class Orbit
public KeplerianOrbit shiftedBy(double dt)
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.
shiftedBy
in interface TimeShiftable<Orbit>
shiftedBy
in class Orbit
dt
- time shift in secondspublic KeplerianOrbit interpolate(AbsoluteDate date, Stream<Orbit> sample)
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.
Note that this method is designed for small samples only (say up to about 10-20 points) so it can be implemented using polynomial interpolation (typically Hermite interpolation). Using too much points may induce Runge's phenomenon and numerical problems (including NaN appearing).
The interpolated instance is created by polynomial Hermite interpolation on Keplerian elements, without derivatives (which means the interpolation falls back to Lagrange interpolation only).
As this implementation of interpolation is polynomial, it should be used only with small samples (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).
If orbit interpolation on large samples is needed, using the Ephemeris
class is a better way than using this
low-level interpolation. The Ephemeris class automatically handles selection of
a neighboring sub-sample with a predefined number of point from a large global sample
in a thread-safe way.
date
- interpolation datesample
- sample points on which interpolation should be doneprotected double[][] computeJacobianMeanWrtCartesian()
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.
computeJacobianMeanWrtCartesian
in class Orbit
Orbit.computeJacobianEccentricWrtCartesian()
,
Orbit.computeJacobianTrueWrtCartesian()
protected double[][] computeJacobianEccentricWrtCartesian()
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.
computeJacobianEccentricWrtCartesian
in class Orbit
Orbit.computeJacobianMeanWrtCartesian()
,
Orbit.computeJacobianTrueWrtCartesian()
protected double[][] computeJacobianTrueWrtCartesian()
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.
computeJacobianTrueWrtCartesian
in class Orbit
Orbit.computeJacobianMeanWrtCartesian()
,
Orbit.computeJacobianEccentricWrtCartesian()
public void addKeplerContribution(PositionAngle type, double gm, double[] pDot)
This method is used by integration-based propagators to evaluate the part of Keplerian motion to evolution of the orbital state.
addKeplerContribution
in class Orbit
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)Copyright © 2002-2020 CS Group. All rights reserved.