org.orekit.propagation.analytical

Class AbstractAnalyticalPropagator

java.lang.Object

org.orekit.propagation.AbstractPropagator

org.orekit.propagation.analytical.AbstractAnalyticalPropagator

All Implemented Interfaces:

Propagator, PVCoordinatesProvider

Direct Known Subclasses:

AdapterPropagator, EcksteinHechlerPropagator, Ephemeris, IntegratedEphemeris, KeplerianPropagator, TLEPropagator

public abstract class AbstractAnalyticalPropagator
extends AbstractPropagator

Common handling of Propagator methods for analytical propagators.

This abstract class allows to provide easily the full set of Propagator methods, including all propagation modes support and discrete events support for any simple propagation method. Only two methods must be implemented by derived classes: propagateOrbit(AbsoluteDate) and getMass(AbsoluteDate). The first method should perform straightforward propagation starting from some internally stored initial state up to the specified target date.

Author:

Luc Maisonobe

Field Summary

Fields inherited from interface org.orekit.propagation.Propagator

DEFAULT_LAW, DEFAULT_MASS, EPHEMERIS_GENERATION_MODE, MASTER_MODE, SLAVE_MODE

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractAnalyticalPropagator(AttitudeProvider attitudeProvider) Build a new instance.

Method Summary

Methods

Modifier and Type	Method and Description
protected SpacecraftState	acceptStep(AbsoluteDate target, double epsilon) Accept a step, triggering events and step handlers.
<T extends EventDetector> void	addEventDetector(T detector) Add an event detector.
protected SpacecraftState	basicPropagate(AbsoluteDate date) Propagate an orbit without any fancy features.
void	clearEventsDetectors() Remove all events detectors.
Collection<EventDetector>	getEventsDetectors() Get all the events detectors that have been added.
BoundedPropagator	getGeneratedEphemeris() Get the ephemeris generated during propagation.
protected abstract double	getMass(AbsoluteDate date) Get the mass.
PVCoordinatesProvider	getPvProvider() Get PV coordinates provider.
SpacecraftState	propagate(AbsoluteDate start, AbsoluteDate target) Propagate from a start date towards a target date.
protected abstract Orbit	propagateOrbit(AbsoluteDate date) Extrapolate an orbit up to a specific target date.

Methods inherited from class org.orekit.propagation.AbstractPropagator

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

Methods inherited from class java.lang.Object

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

Constructor Detail

AbstractAnalyticalPropagator

protected AbstractAnalyticalPropagator(AttitudeProvider attitudeProvider)

Build a new instance.

Parameters:

attitudeProvider - provider for attitude computation

Method Detail

getGeneratedEphemeris

public BoundedPropagator getGeneratedEphemeris()

Get the ephemeris generated during propagation.

Specified by:

getGeneratedEphemeris in interface Propagator

Specified by:

getGeneratedEphemeris in class AbstractPropagator

Returns:

generated ephemeris

See Also:

Propagator.setEphemerisMode()

addEventDetector

public <T extends EventDetector> void addEventDetector(T detector)

Add an event detector.

Specified by:

addEventDetector in interface Propagator

Specified by:

addEventDetector in class AbstractPropagator

Type Parameters:

T - class type for the generic version

Parameters:

detector - event detector to add

See Also:

Propagator.clearEventsDetectors(), Propagator.getEventsDetectors()

getEventsDetectors

public Collection<EventDetector> getEventsDetectors()

Get all the events detectors that have been added.

Specified by:

getEventsDetectors in interface Propagator

Specified by:

getEventsDetectors in class AbstractPropagator

Returns:

an unmodifiable collection of the added detectors

See Also:

Propagator.addEventDetector(EventDetector), Propagator.clearEventsDetectors()

clearEventsDetectors

public void clearEventsDetectors()

Remove all events detectors.

Specified by:

clearEventsDetectors in interface Propagator

Specified by:

clearEventsDetectors in class AbstractPropagator

See Also:

Propagator.addEventDetector(EventDetector), Propagator.getEventsDetectors()

propagate

public SpacecraftState propagate(AbsoluteDate start,
                        AbsoluteDate target)
                          throws PropagationException

Propagate from a start date towards a target date.

Those propagators use a start date and a target date to compute the propagated state. For propagators using event detection mechanism, if the provided start date is different from the initial state date, a first, simple propagation is performed, without processing any event computation. Then complete propagation is performed from start date to target date.

Parameters:

start - start date from which orbit state should be propagated

target - target date to which orbit state should be propagated

Returns:

propagated state

Throws:

PropagationException - if state cannot be propagated

acceptStep

protected SpacecraftState acceptStep(AbsoluteDate target,
                         double epsilon)
                              throws OrekitException,
                                     TooManyEvaluationsException,
                                     NoBracketingException

Accept a step, triggering events and step handlers.

Parameters:

target - final propagation time

epsilon - threshold for end date detection

Returns:

state at the end of the step

Throws:

OrekitException - if the switching function cannot be evaluated

TooManyEvaluationsException - if an event cannot be located

NoBracketingException - if bracketing cannot be performed

getMass

protected abstract double getMass(AbsoluteDate date)
                           throws PropagationException

Get the mass.

Parameters:

date - target date for the orbit

Returns:

mass mass

Throws:

PropagationException - if some parameters are out of bounds

getPvProvider

public PVCoordinatesProvider getPvProvider()

Get PV coordinates provider.

Returns:

PV coordinates provider

propagateOrbit

protected abstract Orbit propagateOrbit(AbsoluteDate date)
                                 throws PropagationException

Extrapolate an orbit up to a specific target date.

Parameters:

date - target date for the orbit

Returns:

extrapolated parameters

Throws:

PropagationException - if some parameters are out of bounds

basicPropagate

protected SpacecraftState basicPropagate(AbsoluteDate date)
                                  throws PropagationException

Propagate an orbit without any fancy features.

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

Parameters:

date - target date for propagation

Returns:

state at specified date

Throws:

PropagationException - if propagation cannot reach specified date