org.orekit.propagation.analytical.gnss

Class GPSPropagator

java.lang.Object

org.orekit.propagation.AbstractPropagator

org.orekit.propagation.analytical.AbstractAnalyticalPropagator

org.orekit.propagation.analytical.gnss.GPSPropagator

All Implemented Interfaces:

Propagator, PVCoordinatesProvider

public class GPSPropagator
extends AbstractAnalyticalPropagator

This class aims at propagating a GPS orbit from GPSOrbitalElements.

Since:

8.0

Author:

Pascal Parraud

See Also:

GPS Interface Specification

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	GPSPropagator.Builder This nested class aims at building a GPSPropagator.

Field Summary

Fields inherited from interface org.orekit.propagation.Propagator

DEFAULT_LAW, DEFAULT_MASS, EPHEMERIS_GENERATION_MODE, MASTER_MODE, SLAVE_MODE

Method Summary

Modifier and Type	Method and Description
Frame	getECEF() Gets the Earth Centered Earth Fixed frame used to propagate GPS orbits according to the GPS Interface Specification.
Frame	getECI() Gets the Earth Centered Inertial frame used to propagate the orbit.
Frame	getFrame() Get the frame in which the orbit is propagated.
GPSOrbitalElements	getGPSOrbitalElements() Gets the underlying GPS orbital elements.
protected double	getMass(AbsoluteDate date) Get the mass.
static double	getMU() Get the Earth gravity coefficient used for GPS propagation.
PVCoordinates	propagateInEcef(AbsoluteDate date) Gets the PVCoordinates of the GPS SV in ECEF frame.
protected Orbit	propagateOrbit(AbsoluteDate date) Extrapolate an orbit up to a specific target date.
void	resetInitialState(SpacecraftState state) Reset the propagator initial state.
protected void	resetIntermediateState(SpacecraftState state, boolean forward) Reset an intermediate state.

Methods inherited from class org.orekit.propagation.analytical.AbstractAnalyticalPropagator

acceptStep, addEventDetector, basicPropagate, clearEventsDetectors, getEventsDetectors, getGeneratedEphemeris, getPvProvider, propagate

Methods inherited from class org.orekit.propagation.AbstractPropagator

addAdditionalStateProvider, getAdditionalStateProviders, getAttitudeProvider, getFixedStepSize, getInitialState, getManagedAdditionalStates, getMode, getPVCoordinates, getStartDate, getStepHandler, isAdditionalStateManaged, propagate, setAttitudeProvider, setEphemerisMode, setEphemerisMode, setMasterMode, setMasterMode, setSlaveMode, setStartDate, updateAdditionalStates

Methods inherited from class java.lang.Object

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

Method Detail

propagateInEcef

public PVCoordinates propagateInEcef(AbsoluteDate date)

Gets the PVCoordinates of the GPS SV in ECEF frame.

The algorithm is defined at Table 20-IV from IS-GPS-200 document, with automatic differentiation added to compute velocity and acceleration.

Parameters:

date - the computation date

Returns:

the GPS SV PVCoordinates in ECEF frame

getMU

public static double getMU()

Get the Earth gravity coefficient used for GPS propagation.

Returns:

the Earth gravity coefficient.

getGPSOrbitalElements

public GPSOrbitalElements getGPSOrbitalElements()

Gets the underlying GPS orbital elements.

Returns:

the underlying GPS orbital elements

getECI

public Frame getECI()

Gets the Earth Centered Inertial frame used to propagate the orbit.

Returns:

the ECI frame

getECEF

public Frame getECEF()

Gets the Earth Centered Earth Fixed frame used to propagate GPS orbits according to the GPS Interface Specification.

This frame is assimilated to the WGS84 ECEF.

Returns:

the ECEF frame

getFrame

public Frame getFrame()

Get the frame in which the orbit is propagated.

The propagation frame is the definition frame of the initial state, so this method should be called after this state has been set, otherwise it may return null.

Specified by:

getFrame in interface Propagator

Overrides:

getFrame in class AbstractPropagator

Returns:

frame in which the orbit is propagated

See Also:

Propagator.resetInitialState(SpacecraftState)

resetInitialState

public void resetInitialState(SpacecraftState state)
                       throws OrekitException

Reset the propagator initial state.

Specified by:

resetInitialState in interface Propagator

Overrides:

resetInitialState in class AbstractPropagator

Parameters:

state - new initial state to consider

Throws:

OrekitException - if initial state cannot be reset

resetIntermediateState

protected void resetIntermediateState(SpacecraftState state,
                                      boolean forward)
                               throws OrekitException

Reset an intermediate state.

Specified by:

resetIntermediateState in class AbstractAnalyticalPropagator

Parameters:

state - new intermediate state to consider

forward - if true, the intermediate state is valid for propagations after itself

Throws:

OrekitException - if initial state cannot be reset

getMass

protected double getMass(AbsoluteDate date)

Get the mass.

Specified by:

getMass in class AbstractAnalyticalPropagator

Parameters:

date - target date for the orbit

Returns:

mass mass

propagateOrbit

protected Orbit propagateOrbit(AbsoluteDate date)
                        throws OrekitException

Extrapolate an orbit up to a specific target date.

Specified by:

propagateOrbit in class AbstractAnalyticalPropagator

Parameters:

date - target date for the orbit

Returns:

extrapolated parameters

Throws:

OrekitException - if some parameters are out of bounds