Orbit (ORbit Extrapolation KIT 7.1 API)

java.lang.Object
- org.orekit.orbits.Orbit

All Implemented Interfaces:

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

Direct Known Subclasses:

CartesianOrbit, CircularOrbit, EquinoctialOrbit, KeplerianOrbit
```
public abstract class Orbit
extends Object
implements TimeStamped, TimeShiftable<Orbit>, TimeInterpolable<Orbit>, Serializable, PVCoordinatesProvider
```
This class handles orbital parameters.
For user convenience, both the Cartesian and the equinoctial elements are provided by this class, regardless of the canonical representation implemented in the derived class (which may be classical keplerian elements for example).

The parameters are defined in a frame specified by the user. It is important to make sure this frame is consistent: it probably is inertial and centered on the central body. This information is used for example by some force models.

The object OrbitalParameters is guaranteed to be immutable.

Author:

Luc Maisonobe, Guylaine Prat, Fabien Maussion, Véronique Pommier-Maurussane

See Also:
Serialized Form

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`Orbit(Frame frame, AbsoluteDate date, double mu)` Default constructor.
`protected`	`Orbit(TimeStampedPVCoordinates pvCoordinates, Frame frame, double mu)` Set the orbit from Cartesian parameters.

Method Summary

Methods
Modifier and Type	Method and Description
`abstract void`	`addKeplerContribution(PositionAngle type, double gm, double[] pDot)` Add the contribution of the Keplerian motion to parameters derivatives
`protected abstract double[][]`	`computeJacobianEccentricWrtCartesian()` Compute the Jacobian of the orbital parameters with eccentric angle with respect to the Cartesian parameters.
`protected abstract double[][]`	`computeJacobianMeanWrtCartesian()` Compute the Jacobian of the orbital parameters with mean angle with respect to the Cartesian parameters.
`protected abstract double[][]`	`computeJacobianTrueWrtCartesian()` Compute the Jacobian of the orbital parameters with true angle with respect to the Cartesian parameters.
`protected static void`	`fillHalfRow(double a, Vector3D v, double[] row, int j)` Fill a Jacobian half row with a single vector.
`protected static void`	`fillHalfRow(double a1, Vector3D v1, double a2, Vector3D v2, double[] row, int j)` Fill a Jacobian half row with a linear combination of vectors.
`protected static void`	`fillHalfRow(double a1, Vector3D v1, double a2, Vector3D v2, double a3, Vector3D v3, double[] row, int j)` Fill a Jacobian half row with a linear combination of vectors.
`protected static void`	`fillHalfRow(double a1, Vector3D v1, double a2, Vector3D v2, double a3, Vector3D v3, double a4, Vector3D v4, double[] row, int j)` Fill a Jacobian half row with a linear combination of vectors.
`protected static void`	`fillHalfRow(double a1, Vector3D v1, double a2, Vector3D v2, double a3, Vector3D v3, double a4, Vector3D v4, double a5, Vector3D v5, double[] row, int j)` Fill a Jacobian half row with a linear combination of vectors.
`protected static void`	`fillHalfRow(double a1, Vector3D v1, double a2, Vector3D v2, double a3, Vector3D v3, double a4, Vector3D v4, double a5, Vector3D v5, double a6, Vector3D v6, double[] row, int j)` Fill a Jacobian half row with a linear combination of vectors.
`abstract double`	`getA()` Get the semi-major axis.
`AbsoluteDate`	`getDate()` Get the date of orbital parameters.
`abstract double`	`getE()` Get the eccentricity.
`abstract double`	`getEquinoctialEx()` Get the first component of the equinoctial eccentricity vector.
`abstract double`	`getEquinoctialEy()` Get the second component of the equinoctial eccentricity vector.
`Frame`	`getFrame()` Get the frame in which the orbital parameters are defined.
`abstract double`	`getHx()` Get the first component of the inclination vector.
`abstract double`	`getHy()` Get the second component of the inclination vector.
`abstract double`	`getI()` Get the inclination.
`void`	`getJacobianWrtCartesian(PositionAngle type, double[][] jacobian)` Compute the Jacobian of the orbital parameters with respect to the Cartesian parameters.
`void`	`getJacobianWrtParameters(PositionAngle type, double[][] jacobian)` Compute the Jacobian of the Cartesian parameters with respect to the orbital parameters.
`double`	`getKeplerianMeanMotion()` Get the keplerian mean motion.
`double`	`getKeplerianPeriod()` Get the keplerian period.
`abstract double`	`getLE()` Get the eccentric longitude argument.
`abstract double`	`getLM()` Get the mean longitude argument.
`abstract double`	`getLv()` Get the true longitude argument.
`double`	`getMu()` Get the central acceleration constant.
`TimeStampedPVCoordinates`	`getPVCoordinates()` Get the `TimeStampedPVCoordinates` in definition frame.
`TimeStampedPVCoordinates`	`getPVCoordinates(AbsoluteDate otherDate, Frame otherFrame)` Get the `PVCoordinates` of the body in the selected frame.
`TimeStampedPVCoordinates`	`getPVCoordinates(Frame outputFrame)` Get the `TimeStampedPVCoordinates` in a specified frame.
`abstract OrbitType`	`getType()` Get the orbit type.
`protected abstract TimeStampedPVCoordinates`	`initPVCoordinates()` Compute the position/velocity coordinates from the canonical parameters.
`abstract Orbit`	`shiftedBy(double dt)` Get a time-shifted orbit.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.time.TimeInterpolable
interpolate

- Constructor Detail
  - Orbit
```
protected Orbit(Frame frame,
     AbsoluteDate date,
     double mu)
         throws IllegalArgumentException
```
    Default constructor. Build a new instance with arbitrary default elements.
    
    Parameters:
    frame - the frame in which the parameters are defined (must be a pseudo-inertial frame)
    date - date of the orbital parameters
    mu - central attraction coefficient (m^3/s^2)
    
    Throws:
    
    IllegalArgumentException - if frame is not a pseudo-inertial frame
  - Orbit
```
protected Orbit(TimeStampedPVCoordinates pvCoordinates,
     Frame frame,
     double mu)
         throws IllegalArgumentException
```
    Set the orbit from Cartesian parameters.
    The acceleration provided in pvCoordinates is accessible using getPVCoordinates() and getPVCoordinates(Frame). All other methods use mu and the position to compute the acceleration, including shiftedBy(double) and getPVCoordinates(AbsoluteDate, Frame).
    
    Parameters:
    pvCoordinates - the position and velocity in the inertial frame
    frame - the frame in which the TimeStampedPVCoordinates are defined (must be a pseudo-inertial frame)
    mu - central attraction coefficient (m^3/s^2)
    
    Throws:
    
    IllegalArgumentException - if frame is not a pseudo-inertial frame
- Method Detail
  - getType
```
public abstract OrbitType getType()
```
    Get the orbit type.
    
    Returns:
    orbit type
  - getFrame
```
public Frame getFrame()
```
    Get the frame in which the orbital parameters are defined.
    
    Returns:
    frame in which the orbital parameters are defined
  - getA
```
public abstract double getA()
```
    Get the semi-major axis.
    Note that the semi-major axis is considered negative for hyperbolic orbits.
    
    Returns:
    semi-major axis (m)
  - getEquinoctialEx
```
public abstract double getEquinoctialEx()
```
    Get the first component of the equinoctial eccentricity vector.
    
    Returns:
    first component of the equinoctial eccentricity vector
  - getEquinoctialEy
```
public abstract double getEquinoctialEy()
```
    Get the second component of the equinoctial eccentricity vector.
    
    Returns:
    second component of the equinoctial eccentricity vector
  - getHx
```
public abstract double getHx()
```
    Get the first component of the inclination vector.
    
    Returns:
    first component of the inclination vector
  - getHy
```
public abstract double getHy()
```
    Get the second component of the inclination vector.
    
    Returns:
    second component of the inclination vector
  - getLE
```
public abstract double getLE()
```
    Get the eccentric longitude argument.
    
    Returns:
    E + ω + Ω eccentric longitude argument (rad)
  - getLv
```
public abstract double getLv()
```
    Get the true longitude argument.
    
    Returns:
    v + ω + Ω true longitude argument (rad)
  - getLM
```
public abstract double getLM()
```
    Get the mean longitude argument.
    
    Returns:
    M + ω + Ω mean longitude argument (rad)
  - getE
```
public abstract double getE()
```
    Get the eccentricity.
    
    Returns:
    eccentricity
  - getI
```
public abstract double getI()
```
    Get the inclination.
    
    Returns:
    inclination (rad)
  - getMu
```
public double getMu()
```
    Get the central acceleration constant.
    
    Returns:
    central acceleration constant
  - getKeplerianPeriod
```
public double getKeplerianPeriod()
```
    Get the keplerian period.
    The keplerian period is computed directly from semi major axis and central acceleration constant.
    
    Returns:
    keplerian period in seconds, or positive infinity for hyperbolic orbits
  - getKeplerianMeanMotion
```
public double getKeplerianMeanMotion()
```
    Get the keplerian mean motion.
    The keplerian mean motion is computed directly from semi major axis and central acceleration constant.
    
    Returns:
    keplerian mean motion in radians per second
  - getDate
```
public AbsoluteDate getDate()
```
    Get the date of orbital parameters.
    
    Specified by:
    
    getDate in interface TimeStamped
    
    Returns:
    date of the orbital parameters
  - getPVCoordinates
```
public TimeStampedPVCoordinates getPVCoordinates(Frame outputFrame)
                                          throws OrekitException
```
    Get the TimeStampedPVCoordinates in a specified frame.
    
    Parameters:
    outputFrame - frame in which the position/velocity coordinates shall be computed
    
    Returns:
    pvCoordinates in the specified output frame
    
    Throws:
    
    OrekitException - if transformation between frames cannot be computed
    See Also:
    getPVCoordinates()
  - getPVCoordinates
```
public TimeStampedPVCoordinates getPVCoordinates(AbsoluteDate otherDate,
                                        Frame otherFrame)
                                          throws OrekitException
```
    Get the PVCoordinates of the body in the selected frame.
    
    Specified by:
    
    getPVCoordinates in interface PVCoordinatesProvider
    
    Parameters:
    otherDate - current date
    otherFrame - the frame where to define the position
    
    Returns:
    time-stamped position/velocity of the body (m and m/s)
    
    Throws:
    
    OrekitException - if position cannot be computed in given frame
  - getPVCoordinates
```
public TimeStampedPVCoordinates getPVCoordinates()
```
    Get the TimeStampedPVCoordinates in definition frame.
    
    Returns:
    pvCoordinates in the definition frame
    See Also:
    getPVCoordinates(Frame)
  - initPVCoordinates
```
protected abstract TimeStampedPVCoordinates initPVCoordinates()
```
    Compute the position/velocity coordinates from the canonical parameters.
    
    Returns:
    computed position/velocity coordinates
  - shiftedBy
```
public abstract Orbit shiftedBy(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:
    
    shiftedBy in interface TimeShiftable<Orbit>
    
    Parameters:
    dt - time shift in seconds
    
    Returns:
    a new orbit, shifted with respect to the instance (which is immutable)
  - getJacobianWrtCartesian
```
public void getJacobianWrtCartesian(PositionAngle type,
                           double[][] jacobian)
```
    Compute the Jacobian of the orbital parameters 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 corresponds to one orbital parameter whereas columns 0 to 5 correspond to the Cartesian coordinates x, y, z, xDot, yDot and zDot.
    
    Parameters:
    type - type of the position angle to use
    jacobian - placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix is larger than 6x6, only the 6x6 upper left corner will be modified
  - getJacobianWrtParameters
```
public void getJacobianWrtParameters(PositionAngle type,
                            double[][] jacobian)
```
    Compute the Jacobian of the Cartesian parameters with respect to the orbital parameters.
    Element jacobian[i][j] is the derivative of Cartesian coordinate i of the orbit with respect to orbital parameter j. This means each row corresponds to one Cartesian coordinate x, y, z, xdot, ydot, zdot whereas columns 0 to 5 correspond to the orbital parameters.
    
    Parameters:
    type - type of the position angle to use
    jacobian - placeholder 6x6 (or larger) matrix to be filled with the Jacobian, if matrix is larger than 6x6, only the 6x6 upper left corner will be modified
  - computeJacobianMeanWrtCartesian
```
protected abstract 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.
    
    Returns:
    6x6 Jacobian matrix
    See Also:
    computeJacobianEccentricWrtCartesian(), computeJacobianTrueWrtCartesian()
  - computeJacobianEccentricWrtCartesian
```
protected abstract 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.
    
    Returns:
    6x6 Jacobian matrix
    See Also:
    computeJacobianMeanWrtCartesian(), computeJacobianTrueWrtCartesian()
  - computeJacobianTrueWrtCartesian
```
protected abstract 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.
    
    Returns:
    6x6 Jacobian matrix
    See Also:
    computeJacobianMeanWrtCartesian(), computeJacobianEccentricWrtCartesian()
  - addKeplerContribution
```
public abstract void addKeplerContribution(PositionAngle 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.
    
    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)
  - fillHalfRow
```
protected static void fillHalfRow(double a,
               Vector3D v,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a single vector.
    
    Parameters:
    a - coefficient of the vector
    v - vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  - fillHalfRow
```
protected static void fillHalfRow(double a1,
               Vector3D v1,
               double a2,
               Vector3D v2,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a linear combination of vectors.
    
    Parameters:
    a1 - coefficient of the first vector
    v1 - first vector
    a2 - coefficient of the second vector
    v2 - second vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  - fillHalfRow
```
protected static void fillHalfRow(double a1,
               Vector3D v1,
               double a2,
               Vector3D v2,
               double a3,
               Vector3D v3,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a linear combination of vectors.
    
    Parameters:
    a1 - coefficient of the first vector
    v1 - first vector
    a2 - coefficient of the second vector
    v2 - second vector
    a3 - coefficient of the third vector
    v3 - third vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  - fillHalfRow
```
protected static void fillHalfRow(double a1,
               Vector3D v1,
               double a2,
               Vector3D v2,
               double a3,
               Vector3D v3,
               double a4,
               Vector3D v4,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a linear combination of vectors.
    
    Parameters:
    a1 - coefficient of the first vector
    v1 - first vector
    a2 - coefficient of the second vector
    v2 - second vector
    a3 - coefficient of the third vector
    v3 - third vector
    a4 - coefficient of the fourth vector
    v4 - fourth vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  - fillHalfRow
```
protected static void fillHalfRow(double a1,
               Vector3D v1,
               double a2,
               Vector3D v2,
               double a3,
               Vector3D v3,
               double a4,
               Vector3D v4,
               double a5,
               Vector3D v5,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a linear combination of vectors.
    
    Parameters:
    a1 - coefficient of the first vector
    v1 - first vector
    a2 - coefficient of the second vector
    v2 - second vector
    a3 - coefficient of the third vector
    v3 - third vector
    a4 - coefficient of the fourth vector
    v4 - fourth vector
    a5 - coefficient of the fifth vector
    v5 - fifth vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)
  - fillHalfRow
```
protected static void fillHalfRow(double a1,
               Vector3D v1,
               double a2,
               Vector3D v2,
               double a3,
               Vector3D v3,
               double a4,
               Vector3D v4,
               double a5,
               Vector3D v5,
               double a6,
               Vector3D v6,
               double[] row,
               int j)
```
    Fill a Jacobian half row with a linear combination of vectors.
    
    Parameters:
    a1 - coefficient of the first vector
    v1 - first vector
    a2 - coefficient of the second vector
    v2 - second vector
    a3 - coefficient of the third vector
    v3 - third vector
    a4 - coefficient of the fourth vector
    v4 - fourth vector
    a5 - coefficient of the fifth vector
    v5 - fifth vector
    a6 - coefficient of the sixth vector
    v6 - sixth vector
    row - Jacobian matrix row
    j - index of the first element to set (row[j], row[j+1] and row[j+2] will all be set)

Class Orbit

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface org.orekit.time.TimeInterpolable

Constructor Detail

Orbit

Orbit

Method Detail

getType

getFrame

getA

getEquinoctialEx

getEquinoctialEy

getHx

getHy

getLE

getLv

getLM

getE

getI

getMu

getKeplerianPeriod

getKeplerianMeanMotion

getDate

getPVCoordinates

getPVCoordinates

getPVCoordinates

initPVCoordinates

shiftedBy

getJacobianWrtCartesian

getJacobianWrtParameters

computeJacobianMeanWrtCartesian

computeJacobianEccentricWrtCartesian

computeJacobianTrueWrtCartesian

addKeplerContribution

fillHalfRow

fillHalfRow

fillHalfRow

fillHalfRow

fillHalfRow

fillHalfRow