org.orekit.propagation

Class AbstractPropagator

java.lang.Object

org.orekit.propagation.AbstractPropagator

All Implemented Interfaces:

Propagator, PVCoordinatesProvider

Direct Known Subclasses:

AbstractAnalyticalPropagator, AbstractIntegratedPropagator

public abstract class AbstractPropagator
extends Object
implements Propagator

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.

Author:

Luc Maisonobe

Field Summary

Fields inherited from interface org.orekit.propagation.Propagator

DEFAULT_MASS

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractPropagator() Build a new instance.

Method Summary

Modifier and Type	Method and Description
void	addAdditionalStateProvider(AdditionalStateProvider provider) Add a set of user-specified state parameters to be computed along with the orbit propagation.
protected AbstractMatricesHarvester	createHarvester(String stmName, RealMatrix initialStm, DoubleArrayDictionary initialJacobianColumns) Create the harvester suitable for propagator.
List<AdditionalStateProvider>	getAdditionalStateProviders() Get an unmodifiable list of providers for additional state.
AttitudeProvider	getAttitudeProvider() Get attitude provider.
Frame	getFrame() Get the frame in which the orbit is propagated.
protected AbstractMatricesHarvester	getHarvester() Get the harvester.
SpacecraftState	getInitialState() Get the propagator initial state.
String[]	getManagedAdditionalStates() Get all the names of all managed states.
StepHandlerMultiplexer	getMultiplexer() Get the multiplexer holding all step handlers.
TimeStampedPVCoordinates	getPVCoordinates(AbsoluteDate date, Frame frame) Get the PVCoordinates of the body in the selected frame.
protected AbsoluteDate	getStartDate() Get the start date.
protected void	initializeAdditionalStates(AbsoluteDate target) Initialize the additional state providers at the start of propagation.
protected void	initializePropagation() Initialize propagation.
boolean	isAdditionalStateManaged(String name) Check if an additional state is managed.
SpacecraftState	propagate(AbsoluteDate target) Propagate towards a target date.
void	resetInitialState(SpacecraftState state) Reset the propagator initial state.
void	setAttitudeProvider(AttitudeProvider attitudeProvider) Set attitude provider.
protected void	setStartDate(AbsoluteDate startDate) Set a start date.
MatricesHarvester	setupMatricesComputation(String stmName, RealMatrix initialStm, DoubleArrayDictionary initialJacobianColumns) Set up computation of State Transition Matrix and Jacobians matrix with respect to parameters.
protected void	stateChanged(SpacecraftState state) Notify about a state change.
protected SpacecraftState	updateAdditionalStates(SpacecraftState original) Update state by adding all additional states.
protected SpacecraftState	updateUnmanagedStates(SpacecraftState original) Update state by adding unmanaged states.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.propagation.Propagator

addEventDetector, clearEventsDetectors, clearStepHandlers, getDefaultLaw, getEphemerisGenerator, getEventsDetectors, propagate, setStepHandler, setStepHandler

Constructor Detail

AbstractPropagator

protected AbstractPropagator()

Build a new instance.

Method Detail

setStartDate

protected void setStartDate(AbsoluteDate startDate)

Set a start date.

Parameters:

startDate - start date

getStartDate

protected AbsoluteDate getStartDate()

Get the start date.

Returns:

start date

getAttitudeProvider

public AttitudeProvider getAttitudeProvider()

Get attitude provider.

Specified by:

getAttitudeProvider in interface Propagator

Returns:

attitude provider

setAttitudeProvider

public void setAttitudeProvider(AttitudeProvider attitudeProvider)

Set attitude provider.

Specified by:

setAttitudeProvider in interface Propagator

Parameters:

attitudeProvider - attitude provider

getInitialState

public SpacecraftState getInitialState()

Get the propagator initial state.

Specified by:

getInitialState in interface Propagator

Returns:

initial state

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

Returns:

frame in which the orbit is propagated

See Also:

Propagator.resetInitialState(SpacecraftState)

resetInitialState

public void resetInitialState(SpacecraftState state)

Reset the propagator initial state.

Specified by:

resetInitialState in interface Propagator

Parameters:

state - new initial state to consider

getMultiplexer

public StepHandlerMultiplexer getMultiplexer()

Get the multiplexer holding all step handlers.

Specified by:

getMultiplexer in interface Propagator

Returns:

multiplexer holding all step handlers

addAdditionalStateProvider

public void addAdditionalStateProvider(AdditionalStateProvider provider)

Add a set of user-specified state parameters to be computed along with the orbit propagation.

Specified by:

addAdditionalStateProvider in interface Propagator

Parameters:

provider - provider for additional state

getAdditionalStateProviders

public List<AdditionalStateProvider> getAdditionalStateProviders()

Get an unmodifiable list of providers for additional state.

Specified by:

getAdditionalStateProviders in interface Propagator

Returns:

providers for the additional states

setupMatricesComputation

public MatricesHarvester setupMatricesComputation(String stmName,
                                                  RealMatrix initialStm,
                                                  DoubleArrayDictionary initialJacobianColumns)

Set up computation of State Transition Matrix and Jacobians matrix with respect to parameters.

If this method is called, both State Transition Matrix and Jacobians with respect to the force models parameters that will be selected when propagation starts will be automatically computed, and the harvester will allow to retrieve them.

The arguments for initial matrices must be compatible with the orbit type and position angle that will be used by the propagator.

The default implementation throws an exception as the method is not supported by all propagators.

Specified by:

setupMatricesComputation in interface Propagator

Parameters:

stmName - State Transition Matrix state name

initialStm - initial State Transition Matrix ∂Y/∂Y₀, if null (which is the most frequent case), assumed to be 6x6 identity

initialJacobianColumns - initial columns of the Jacobians matrix with respect to parameters, if null or if some selected parameters are missing from the dictionary, the corresponding initial column is assumed to be 0

Returns:

harvester to retrieve computed matrices during and after propagation

createHarvester

protected AbstractMatricesHarvester createHarvester(String stmName,
                                                    RealMatrix initialStm,
                                                    DoubleArrayDictionary initialJacobianColumns)

Create the harvester suitable for propagator.

Parameters:

stmName - State Transition Matrix state name

initialStm - initial State Transition Matrix ∂Y/∂Y₀, if null (which is the most frequent case), assumed to be 6x6 identity

initialJacobianColumns - initial columns of the Jacobians matrix with respect to parameters, if null or if some selected parameters are missing from the dictionary, the corresponding initial column is assumed to be 0

Returns:

harvester to retrieve computed matrices during and after propagation

Since:

11.1

getHarvester

protected AbstractMatricesHarvester getHarvester()

Get the harvester.

Returns:

harvester, or null if it was not created

Since:

11.1

updateUnmanagedStates

protected SpacecraftState updateUnmanagedStates(SpacecraftState original)

Update state by adding unmanaged states.

Parameters:

original - original state

Returns:

updated state, with unmanaged states included

See Also:

updateAdditionalStates(SpacecraftState)

updateAdditionalStates

protected SpacecraftState updateAdditionalStates(SpacecraftState original)

Update state by adding all additional states.

Parameters:

original - original state

Returns:

updated state, with all additional states included (including unmanaged states)

See Also:

addAdditionalStateProvider(AdditionalStateProvider), updateUnmanagedStates(SpacecraftState)

initializeAdditionalStates

protected void initializeAdditionalStates(AbsoluteDate target)

Initialize the additional state providers at the start of propagation.

Parameters:

target - date of propagation. Not equal to initialState.getDate().

Since:

11.2

isAdditionalStateManaged

public boolean isAdditionalStateManaged(String name)

Check if an additional state is managed.

Managed states are states for which the propagators know how to compute its evolution. They correspond to additional states for which a provider has been registered by calling the addAdditionalStateProvider method.

Additional states that are present in the initial state but have no evolution method registered are not considered as managed states. These unmanaged additional states are not lost during propagation, though. Their value are piecewise constant between state resets that may change them if some event handler resetState method is called at an event occurrence and happens to change the unmanaged additional state.

Specified by:

isAdditionalStateManaged in interface Propagator

Parameters:

name - name of the additional state

Returns:

true if the additional state is managed

getManagedAdditionalStates

public String[] getManagedAdditionalStates()

Get all the names of all managed states.

Specified by:

getManagedAdditionalStates in interface Propagator

Returns:

names of all managed states

propagate

public SpacecraftState propagate(AbsoluteDate target)

Propagate towards a target date.

Simple propagators use only the target date as the specification for computing the propagated state. More feature rich propagators can consider other information and provide different operating modes or G-stop facilities to stop at pinpointed events occurrences. In these cases, the target date is only a hint, not a mandatory objective.

Specified by:

propagate in interface Propagator

Parameters:

target - target date towards which orbit state should be propagated

Returns:

propagated state

getPVCoordinates

public TimeStampedPVCoordinates getPVCoordinates(AbsoluteDate date,
                                                 Frame frame)

Get the PVCoordinates of the body in the selected frame.

Specified by:

getPVCoordinates in interface PVCoordinatesProvider

Parameters:

date - current date

frame - the frame where to define the position

Returns:

time-stamped position/velocity of the body (m and m/s)

initializePropagation

protected void initializePropagation()

Initialize propagation.

Since:

10.1

stateChanged

protected void stateChanged(SpacecraftState state)

Notify about a state change.

Parameters:

state - new state