Package org.orekit.files.sp3

Class SP3Segment

java.lang.Object

org.orekit.files.sp3.SP3Segment

All Implemented Interfaces:

EphemerisFile.EphemerisSegment<SP3Coordinate>

public class SP3Segment
extends Object
implements EphemerisFile.EphemerisSegment<SP3Coordinate>

One segment of an SP3Ephemeris.

Since:

12.0

Author:

Thomas Neidhart, Evan Ward, Luc Maisonobe

Constructor Summary

Constructors

Constructor	Description
SP3Segment(double mu, Frame frame, int interpolationSamples, CartesianDerivativesFilter filter)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
void	addCoordinate(SP3Coordinate coord)	Adds a new P/V coordinate.
ClockModel	extractClockModel()	Extract the clock model.
CartesianDerivativesFilter	getAvailableDerivatives()	Get which derivatives of position are available in this ephemeris segment.
List<SP3Coordinate>	getCoordinates()	Get the coordinates for this ephemeris segment in EphemerisFile.EphemerisSegment.getFrame().
Frame	getFrame()	Get the 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.
BoundedPropagator	getPropagator()	View this ephemeris segment as a propagator.
BoundedPropagator	getPropagator(AttitudeProvider attitudeProvider)	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.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.files.general.EphemerisFile.EphemerisSegment

getInertialFrame

Constructor Detail

SP3Segment

public SP3Segment(double mu,
                  Frame frame,
                  int interpolationSamples,
                  CartesianDerivativesFilter filter)

Simple constructor.

Parameters:

mu - standard gravitational parameter to use for creating Orbits from the ephemeris data.

frame - reference frame

interpolationSamples - number of points to use for interpolation

filter - available derivatives

Method Detail

extractClockModel

public ClockModel extractClockModel()

Extract the clock model.

If some clock or clock rate are present in the SP3 files as default values (999999.999999), then they filtered out here when building the clock model, so interpolation will work if at least there are some remaining regular values.

Returns:

extracted clock model

Since:

12.1

getMu

public double getMu()

Get the standard gravitational parameter for the satellite.

Specified by:

getMu in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

the gravitational parameter used in EphemerisFile.EphemerisSegment.getPropagator(AttitudeProvider), in m³/s².

getStart

public AbsoluteDate getStart()

Get the start date of this ephemeris segment.

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

Specified by:

getStart in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

ephemeris segment start date.

getStop

public AbsoluteDate getStop()

Get the end date of this ephemeris segment.

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

Specified by:

getStop in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

ephemeris segment end date.

getFrame

public Frame getFrame()

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

Specified by:

getFrame in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

the reference frame for this segment. Never null.

getInterpolationSamples

public int getInterpolationSamples()

Get the number of samples to use in interpolation.

Specified by:

getInterpolationSamples in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

the number of points to use for interpolation.

getAvailableDerivatives

public CartesianDerivativesFilter getAvailableDerivatives()

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<SP3Coordinate>

Returns:

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

getCoordinates

public List<SP3Coordinate> getCoordinates()

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

Specified by:

getCoordinates in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

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.

addCoordinate

public void addCoordinate(SP3Coordinate coord)

Adds a new P/V coordinate.

Parameters:

coord - the P/V coordinate of the satellite

getPropagator

public 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 must be constructable from the frame specification in the ephemeris file. This condition is met when EphemerisFile.EphemerisSegment.getFrame() return normally. Additionally, EphemerisFile.EphemerisSegment.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.

The attitude provider used is a FrameAlignedProvider aligned with the inertial frame

Each call to this method creates a new propagator.

Specified by:

getPropagator in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Returns:

a propagator for this ephemeris segment.

getPropagator

public BoundedPropagator getPropagator(AttitudeProvider attitudeProvider)

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 must be constructable from the frame specification in the ephemeris file. This condition is met when EphemerisFile.EphemerisSegment.getFrame() return normally. Additionally, EphemerisFile.EphemerisSegment.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.

Specified by:

getPropagator in interface EphemerisFile.EphemerisSegment<SP3Coordinate>

Parameters:

attitudeProvider - provider for attitude computation

Returns:

a propagator for this ephemeris segment.