org.orekit.propagation.analytical
Class AdapterPropagator

java.lang.Object
  org.orekit.propagation.AbstractPropagator
      org.orekit.propagation.analytical.AdapterPropagator

All Implemented Interfaces:

Serializable, Propagator, PVCoordinatesProvider

public class AdapterPropagator
extends AbstractPropagator

Orbit propagator that adapts an underlying propagator, adding differential effects.

This propagator is used when a reference propagator does not handle some effects that we need. A typical example would be an ephemeris that was computed for a reference orbit, and we want to compute a station-keeping maneuver on top of this ephemeris, changing its final state. The principal is to add one or more small maneuvers analytical models to it and use it as a new propagator, which takes the maneuvers into account.

From a space flight dynamics point of view, this is a differential correction approach. From a computer science point of view, this is a use of the decorator design pattern.

Author:

Luc Maisonobe

See Also:

Propagator, SmallManeuverAnalyticalModel, Serialized Form

Nested Class Summary

static interface

AdapterPropagator.DifferentialEffect Interface for orbit differential effects.

Field Summary

Fields inherited from class org.orekit.propagation.AbstractPropagator

MASS

Fields inherited from interface org.orekit.propagation.Propagator

EPHEMERIS_GENERATION_MODE, MASTER_MODE, SLAVE_MODE

Constructor Summary

AdapterPropagator(Propagator reference)
Build a propagator from an underlying reference propagator.

Method Summary

void	addEffect(AdapterPropagator.DifferentialEffect effect) Add a differential effect.
protected SpacecraftState	basicPropagate(AbsoluteDate date) Propagate an orbit without any fancy features.
List<AdapterPropagator.DifferentialEffect>	getEffects() Get the differential effects.
SpacecraftState	getInitialState() Get the propagator initial state.
Propagator	getPropagator() Get the reference propagator.
protected Orbit	propagateOrbit(AbsoluteDate date) Extrapolate an orbit up to a specific target date.
void	resetInitialState(SpacecraftState state) Reset the propagator initial state.

Methods inherited from class org.orekit.propagation.AbstractPropagator

acceptStep, addAdditionalStateProvider, addAdditionalStateProvider, addEventDetector, clearEventsDetectors, getAttitudeProvider, getAttitudeProviderEvents, getAttitudeProviderForces, getEventsDetectors, getFrame, getGeneratedEphemeris, getMode, getPVCoordinates, getPvProvider, manageStateFrame, propagate, propagate, setAttitudeProvider, setAttitudeProviderEvents, setAttitudeProviderForces, setEphemerisMode, setMasterMode, setMasterMode, setOrbitFrame, setSlaveMode, setStartDate

Methods inherited from class java.lang.Object

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

Constructor Detail

AdapterPropagator

public AdapterPropagator(Propagator reference)

Build a propagator from an underlying reference propagator.

The reference propagator can be almost anything, numerical, analytical, and even an ephemeris. It may already take some maneuvers into account.

Parameters:

reference - reference propagator

Method Detail

addEffect

public void addEffect(AdapterPropagator.DifferentialEffect effect)

Add a differential effect.

Parameters:

effect - differential effect

getPropagator

public Propagator getPropagator()

Get the reference propagator.

Returns:

reference propagator

getEffects

public List<AdapterPropagator.DifferentialEffect> getEffects()

Get the differential effects.

Returns:

differential effects models, as an unmodifiable list

getInitialState

public SpacecraftState getInitialState()
                                throws OrekitException

Get the propagator initial state.

Specified by:

getInitialState in interface Propagator

Overrides:

getInitialState in class AbstractPropagator

Returns:

initial state

Throws:

OrekitException - if state cannot be retrieved

resetInitialState

public void resetInitialState(SpacecraftState state)
                       throws PropagationException

Reset the propagator initial state.

Specified by:

resetInitialState in interface Propagator

Overrides:

resetInitialState in class AbstractPropagator

Parameters:

state - new initial state to consider

Throws:

PropagationException - if initial state cannot be reset

basicPropagate

protected SpacecraftState basicPropagate(AbsoluteDate date)
                                  throws PropagationException

Propagate an orbit without any fancy features.

This method is similar in spirit to the AbstractPropagator.propagate(org.orekit.time.AbsoluteDate) method, except that it does not call any handler during propagation, nor any discrete events. It always stop exactly at the specified date.

Overrides:

basicPropagate in class AbstractPropagator

Parameters:

date - target date for propagation

Returns:

state at specified date

Throws:

PropagationException - if propagation cannot reach specified date

propagateOrbit

protected Orbit propagateOrbit(AbsoluteDate date)
                        throws PropagationException

Extrapolate an orbit up to a specific target date.

Specified by:

propagateOrbit in class AbstractPropagator

Parameters:

date - target date for the orbit

Returns:

extrapolated parameters

Throws:

PropagationException - if some parameters are out of bounds