org.orekit.files.sp3

Class SP3File.SP3Ephemeris

java.lang.Object

org.orekit.files.sp3.SP3File.SP3Ephemeris

All Implemented Interfaces:

EphemerisFile.EphemerisSegment, EphemerisFile.SatelliteEphemeris

Enclosing class:

SP3File

public class SP3File.SP3Ephemeris
extends Object
implements EphemerisFile.SatelliteEphemeris, EphemerisFile.EphemerisSegment

An ephemeris for a single satellite in a SP3 file.

Method Summary

Modifier and Type	Method and Description
double	getAccuracy() Get the formal accuracy for this satellite.
CartesianDerivativesFilter	getAvailableDerivatives() Get which derivatives of position are available in this ephemeris segment.
List<SP3File.SP3Coordinate>	getCoordinates() Get the coordinates for this ephemeris segment.
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.
String	getId() Get the satellite ID.
int	getInterpolationSamples() Get the number of samples to use in interpolation.
double	getMu() Get the standard gravitational parameter for the satellite.
BoundedPropagator	getPropagator() View this ephemeris as a propagator, combining data from all segments.
List<SP3File.SP3Ephemeris>	getSegments() Returns a list containing only this.
AbsoluteDate	getStart() Get the start date of the ephemeris.
AbsoluteDate	getStop() Get the end date of the ephemeris.
TimeScale	getTimeScale() Get the time scale for this ephemeris segment.
String	getTimeScaleString() Get the time scale for this ephemeris segment.

Methods inherited from class java.lang.Object

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

Method Detail

getId

public String getId()

Description copied from interface: EphemerisFile.SatelliteEphemeris

Get the satellite ID. The satellite ID is unique only within the same ephemeris file.

Specified by:

getId in interface EphemerisFile.SatelliteEphemeris

Returns:

the satellite's ID, never null.

getMu

public double getMu()

Description copied from interface: EphemerisFile.SatelliteEphemeris

Get the standard gravitational parameter for the satellite.

Specified by:

getMu in interface EphemerisFile.EphemerisSegment

Specified by:

getMu in interface EphemerisFile.SatelliteEphemeris

Returns:

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

getFrameCenterString

public String getFrameCenterString()

Description copied from interface: EphemerisFile.EphemerisSegment

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.

Specified by:

getFrameCenterString in interface EphemerisFile.EphemerisSegment

Returns:

the name of the frame center

getFrameString

public String getFrameString()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the defining frame for this ephemeris segment.

Specified by:

getFrameString in interface EphemerisFile.EphemerisSegment

Returns:

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

getFrame

public Frame getFrame()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the reference frame for this ephemeris segment.

Specified by:

getFrame in interface EphemerisFile.EphemerisSegment

Returns:

the reference frame for this segment. Never null.

getTimeScaleString

public String getTimeScaleString()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the time scale for this ephemeris segment.

Specified by:

getTimeScaleString in interface EphemerisFile.EphemerisSegment

Returns:

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

getTimeScale

public TimeScale getTimeScale()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the time scale for this ephemeris segment.

Specified by:

getTimeScale in interface EphemerisFile.EphemerisSegment

Returns:

the time scale for this segment. Never null.

getInterpolationSamples

public int getInterpolationSamples()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the number of samples to use in interpolation.

Specified by:

getInterpolationSamples in interface EphemerisFile.EphemerisSegment

Returns:

the number of points to use for interpolation.

getAvailableDerivatives

public CartesianDerivativesFilter getAvailableDerivatives()

Description copied from interface: EphemerisFile.EphemerisSegment

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

While EphemerisFile.EphemerisSegment.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.

Specified by:

getAvailableDerivatives in interface EphemerisFile.EphemerisSegment

Returns:

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

getCoordinates

public List<SP3File.SP3Coordinate> getCoordinates()

Description copied from interface: EphemerisFile.EphemerisSegment

Get the coordinates for this ephemeris segment.

Specified by:

getCoordinates in interface EphemerisFile.EphemerisSegment

Returns:

a list of state vectors in chronological order. The coordinates are not necessarily evenly spaced in time. The value of EphemerisFile.EphemerisSegment.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.

getSegments

public List<SP3File.SP3Ephemeris> getSegments()

Returns a list containing only this.

Specified by:

getSegments in interface EphemerisFile.SatelliteEphemeris

Returns:

the segments contained in the ephemeris file for this satellite.

getStart

public AbsoluteDate getStart()

Description copied from interface: EphemerisFile.SatelliteEphemeris

Get the start date of the ephemeris.

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

Specified by:

getStart in interface EphemerisFile.EphemerisSegment

Specified by:

getStart in interface EphemerisFile.SatelliteEphemeris

Returns:

ephemeris start date.

getStop

public AbsoluteDate getStop()

Description copied from interface: EphemerisFile.SatelliteEphemeris

Get the end date of the ephemeris.

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

Specified by:

getStop in interface EphemerisFile.EphemerisSegment

Specified by:

getStop in interface EphemerisFile.SatelliteEphemeris

Returns:

ephemeris end date.

getPropagator

public BoundedPropagator getPropagator()

Description copied from interface: EphemerisFile.SatelliteEphemeris

View this ephemeris as a propagator, combining data from all segments.

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 EphemerisFile.EphemerisSegment.getFrame() and EphemerisFile.EphemerisSegment.getTimeScale() return normally for all segments. If there are multiple segments they must be adjacent such that there are no duplicates or gaps in the ephemeris. The definition of adjacent depends on the ephemeris format as some formats define usable start and stop times that are different from the ephemeris data start and stop times. 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.

Specified by:

getPropagator in interface EphemerisFile.EphemerisSegment

Specified by:

getPropagator in interface EphemerisFile.SatelliteEphemeris

Returns:

a propagator for all the data in this ephemeris file.

getAccuracy

public double getAccuracy()

Get the formal accuracy for this satellite.

The accuracy is limited by the SP3 standard to be a power of 2 in mm. The value returned here is in meters.

Returns:

magnitude of one standard deviation, in m.