org.orekit.files.general

Interface EphemerisFile.EphemerisSegment

All Known Implementing Classes:

OEMFile.EphemeridesBlock, OrekitEphemerisFile.OrekitEphemerisSegment, SP3File.SP3Ephemeris

Enclosing interface:

EphemerisFile

public static interface EphemerisFile.EphemerisSegment

A segment of an ephemeris for a satellite.

Segments are typically used to split an ephemeris around discontinuous events such as maneuvers.

Author:

Evan Ward

See Also:

EphemerisFile, EphemerisFile.SatelliteEphemeris

Method Summary

Modifier and Type	Method and Description
CartesianDerivativesFilter	getAvailableDerivatives() Get which derivatives of position are available in this ephemeris segment.
List<? extends TimeStampedPVCoordinates>	getCoordinates() Get the coordinates for this ephemeris segment in getFrame().
Frame	getFrame() Get the reference frame for this ephemeris segment.
String	getFrameCenterString() Get the name of the center of the coordinate system the ephemeris is provided in.
String	getFrameString() Get the defining frame for this ephemeris segment.
default Frame	getInertialFrame() Get the inertial reference frame for this ephemeris segment.
int	getInterpolationSamples() Get the number of samples to use in interpolation.
double	getMu() Get the standard gravitational parameter for the satellite.
default BoundedPropagator	getPropagator() View this ephemeris segment as a propagator.
AbsoluteDate	getStart() Get the start date of this ephemeris segment.
AbsoluteDate	getStop() Get the end date of this ephemeris segment.
TimeScale	getTimeScale() Get the time scale for this ephemeris segment.
String	getTimeScaleString() Get the time scale for this ephemeris segment.

Method Detail

getMu

double getMu()

Get the standard gravitational parameter for the satellite.

Returns:

the gravitational parameter use in getPropagator(), in m^3 / s^2.

getFrameCenterString

String getFrameCenterString()

Get the name of the center of the coordinate system the ephemeris is provided in. This may be a natural origin, such as the center of the Earth, another satellite, etc.

Returns:

the name of the frame center

getFrameString

String getFrameString()

Get the defining frame for this ephemeris segment.

Returns:

the frame identifier, as specified in the ephemeris file, or null if the ephemeris file does not specify a frame.

getFrame

Frame getFrame()

Get the reference frame for this ephemeris segment. The defining frame for getCoordinates().

Returns:

the reference frame for this segment. Never null.

getInertialFrame

default Frame getInertialFrame()

Get the inertial reference frame for this ephemeris segment. Defines the propagation frame for getPropagator().

The default implementation returns getFrame() if it is inertial. Otherwise it returns Frame.getRoot(). Implementors are encouraged to override this default implementation if a more suitable inertial frame is available.

Returns:

an reference frame that is inertial, i.e. Frame.isPseudoInertial() is true. May be the same as getFrame() if it is inertial.

getTimeScaleString

String getTimeScaleString()

Get the time scale for this ephemeris segment.

Returns:

the time scale identifier, as specified in the ephemeris file, or null if the ephemeris file does not specify a time scale.

getTimeScale

TimeScale getTimeScale()

Get the time scale for this ephemeris segment.

Returns:

the time scale for this segment. Never null.

getInterpolationSamples

int getInterpolationSamples()

Get the number of samples to use in interpolation.

Returns:

the number of points to use for interpolation.

getAvailableDerivatives

CartesianDerivativesFilter getAvailableDerivatives()

Get which derivatives of position are available in this ephemeris segment.

While getCoordinates() always returns position, velocity, and acceleration the return value from this method indicates which of those are in the ephemeris file and are actually valid.

Returns:

a value indicating if the file contains velocity and/or acceleration data.

getCoordinates

List<? extends TimeStampedPVCoordinates> getCoordinates()

Get the coordinates for this ephemeris segment in getFrame().

Returns:

a list of state vectors in chronological order. The coordinates are not necessarily evenly spaced in time. The value of getAvailableDerivatives() indicates if the velocity or accelerations were specified in the file. Any position, velocity, or acceleration coordinates that are not specified in the ephemeris file are zero in the returned values.

getStart

AbsoluteDate getStart()

Get the start date of this ephemeris segment.

The date returned by this method is equivalent to getPropagator().getMinDate().

Returns:

ephemeris segment start date.

getStop

AbsoluteDate getStop()

Get the end date of this ephemeris segment.

The date returned by this method is equivalent to getPropagator().getMaxDate().

Returns:

ephemeris segment end date.

getPropagator

default BoundedPropagator getPropagator()

View this ephemeris segment as a propagator.

In order to view the ephemeris for this satellite as a Propagator several conditions must be met. An Orekit Frame and TimeScale must be constructable from the frame and time scale specification in the ephemeris file. This condition is met when getFrame() and getTimeScale() return normally. Additionally, getMu() must return a valid value. If these conditions are not met an OrekitException may be thrown by this method or by one of the methods of the returned Propagator.

Each call to this method creates a new propagator.

Returns:

a propagator for this ephemeris segment.