Class FieldStateCovariance<T extends CalculusFieldElement<T>>
- java.lang.Object
-
- org.orekit.propagation.FieldStateCovariance<T>
-
- Type Parameters:
T
- type of the field elements
- All Implemented Interfaces:
FieldTimeStamped<T>
public class FieldStateCovariance<T extends CalculusFieldElement<T>> extends Object implements FieldTimeStamped<T>
This class is the representation of a covariance matrix at a given date.Currently, the covariance only represents the orbital elements.
It is possible to change the covariance frame by using the
changeCovarianceFrame(FieldOrbit, Frame)
orchangeCovarianceFrame(FieldOrbit, LOF)
method. These methods are based on Equations (18) and (20) of Covariance Transformations for Satellite Flight Dynamics Operations by David A. SVallado.Finally, covariance orbit type can be changed using the
changeCovarianceType(FieldOrbit, OrbitType, PositionAngle)
method.- Since:
- 12.0
- Author:
- Bryan Cazabonne, Vincent Cucchietti
-
-
Constructor Summary
Constructors Constructor Description FieldStateCovariance(FieldMatrix<T> orbitalCovariance, FieldAbsoluteDate<T> epoch, Frame covarianceFrame, OrbitType orbitType, PositionAngleType angleType)
Constructor.FieldStateCovariance(FieldMatrix<T> orbitalCovariance, FieldAbsoluteDate<T> epoch, LOF lof)
Constructor.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description FieldStateCovariance<T>
changeCovarianceFrame(FieldOrbit<T> orbit, Frame frameOut)
Get the covariance in the output frame.FieldStateCovariance<T>
changeCovarianceFrame(FieldOrbit<T> orbit, LOF lofOut)
Get the covariance in a given local orbital frame.FieldStateCovariance<T>
changeCovarianceType(FieldOrbit<T> orbit, OrbitType outOrbitType, PositionAngleType outAngleType)
Get the covariance matrix in another orbit type.FieldAbsoluteDate<T>
getDate()
Get the date.Frame
getFrame()
Get the covariance frame.LOF
getLOF()
Get the covariance LOF type.FieldMatrix<T>
getMatrix()
Get the covariance matrix.OrbitType
getOrbitType()
Get the covariance orbit type.PositionAngleType
getPositionAngleType()
Get the covariance angle type.FieldStateCovariance<T>
shiftedBy(Field<T> field, FieldOrbit<T> orbit, T dt)
Get a time-shifted covariance matrix.StateCovariance
toStateCovariance()
Get new state covariance instance.-
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.FieldTimeStamped
durationFrom
-
-
-
-
Constructor Detail
-
FieldStateCovariance
public FieldStateCovariance(FieldMatrix<T> orbitalCovariance, FieldAbsoluteDate<T> epoch, LOF lof)
Constructor.- Parameters:
orbitalCovariance
- 6x6 orbital parameters covarianceepoch
- epoch of the covariancelof
- covariance LOF type
-
FieldStateCovariance
public FieldStateCovariance(FieldMatrix<T> orbitalCovariance, FieldAbsoluteDate<T> epoch, Frame covarianceFrame, OrbitType orbitType, PositionAngleType angleType)
Constructor.- Parameters:
orbitalCovariance
- 6x6 orbital parameters covarianceepoch
- epoch of the covariancecovarianceFrame
- covariance frame (inertial or Earth fixed)orbitType
- orbit type of the covariance (CARTESIAN if covarianceFrame is not pseudo-inertial)angleType
- position angle type of the covariance (not used if orbitType is CARTESIAN)
-
-
Method Detail
-
getDate
public FieldAbsoluteDate<T> getDate()
Get the date..- Specified by:
getDate
in interfaceFieldTimeStamped<T extends CalculusFieldElement<T>>
- Returns:
- date attached to the object
-
getMatrix
public FieldMatrix<T> getMatrix()
Get the covariance matrix.- Returns:
- the covariance matrix
-
getOrbitType
public OrbitType getOrbitType()
Get the covariance orbit type.- Returns:
- the covariance orbit type
-
getPositionAngleType
public PositionAngleType getPositionAngleType()
Get the covariance angle type.- Returns:
- the covariance angle type
-
getFrame
public Frame getFrame()
Get the covariance frame.- Returns:
- the covariance frame (can be null)
- See Also:
getLOF()
-
getLOF
public LOF getLOF()
Get the covariance LOF type.- Returns:
- the covariance LOF type (can be null)
- See Also:
getFrame()
-
changeCovarianceType
public FieldStateCovariance<T> changeCovarianceType(FieldOrbit<T> orbit, OrbitType outOrbitType, PositionAngleType outAngleType)
Get the covariance matrix in another orbit type.The covariance orbit type cannot be changed if the covariance matrix is expressed in a
local orbital frame
or a non-pseudo inertial frame.As this type change uses the jacobian matrix of the transformation, it introduces a linear approximation. Hence, the current covariance matrix will not exactly match the new linearized case and the distribution will not follow a generalized Gaussian distribution anymore.
This is based on equation (1) to (6) from "Vallado, D. A. (2004). Covariance transformations for satellite flight dynamics operations."
- Parameters:
orbit
- orbit to which the covariance matrix should correspondoutOrbitType
- target orbit type of the state covariance matrixoutAngleType
- target position angle type of the state covariance matrix- Returns:
- a new covariance state, expressed in the target orbit type with the target position angle
- See Also:
changeCovarianceFrame(FieldOrbit, Frame)
-
changeCovarianceFrame
public FieldStateCovariance<T> changeCovarianceFrame(FieldOrbit<T> orbit, LOF lofOut)
Get the covariance in a given local orbital frame.Changing the covariance frame is a linear process, this method does not introduce approximation unless a change in covariance orbit type is required.
This is based on equation (18) to (20) "from Vallado, D. A. (2004). Covariance transformations for satellite flight dynamics operations."
- Parameters:
orbit
- orbit to which the covariance matrix should correspondlofOut
- output local orbital frame- Returns:
- a new covariance state, expressed in the output local orbital frame
-
changeCovarianceFrame
public FieldStateCovariance<T> changeCovarianceFrame(FieldOrbit<T> orbit, Frame frameOut)
Get the covariance in the output frame.Changing the covariance frame is a linear process, this method does not introduce approximation unless a change in covariance orbit type is required.
This is based on equation (18) to (20) "from Vallado, D. A. (2004). Covariance transformations for satellite flight dynamics operations."
- Parameters:
orbit
- orbit to which the covariance matrix should correspondframeOut
- output frame- Returns:
- a new covariance state, expressed in the output frame
-
shiftedBy
public FieldStateCovariance<T> shiftedBy(Field<T> field, FieldOrbit<T> orbit, T dt)
Get a time-shifted covariance matrix.The shifting model is a linearized, Keplerian one. In other words, it is based on a state transition matrix that is computed assuming Keplerian motion.
Shifting is not intended as a replacement for proper covariance propagation, but should be sufficient for small time shifts or coarse accuracy.
- Parameters:
field
- to which the elements belongorbit
- orbit to which the covariance matrix should corresponddt
- time shift in seconds- Returns:
- a new covariance state, shifted with respect to the instance
-
toStateCovariance
public StateCovariance toStateCovariance()
Get new state covariance instance.- Returns:
- new state covariance instance.
-
-