org.orekit.propagation.semianalytical.dsst.forces

Interface DSSTForceModel

All Known Implementing Classes:

AbstractGaussianContribution, DSSTAtmosphericDrag, DSSTSolarRadiationPressure, DSSTTesseral, DSSTThirdBody, DSSTZonal

public interface DSSTForceModel

This interface represents a force modifying spacecraft motion for a DSSTPropagator.

Objects implementing this interface are intended to be added to a DSST propagator before the propagation is started.

The propagator will call at the very beginning of a propagation the initialize(AuxiliaryElements, boolean) method allowing preliminary computation such as truncation if needed.

Then the propagator will call at each step:

1. the initializeStep(AuxiliaryElements) method. The force model instance will extract all the elements needed before computing the mean element rates.
2. the getMeanElementRate(SpacecraftState) method. The force model instance will extract all the state data needed to compute the mean element rates that contribute to the mean state derivative.
3. the updateShortPeriodTerms(SpacecraftState...) method, if osculating parameters are desired, on a sample of points within the last step.

Author:

Romain Di Constanzo, Pascal Parraud

Method Summary

Modifier and Type	Method and Description
EventDetector[]	getEventsDetectors() Get the discrete events related to the model.
double[]	getMeanElementRate(SpacecraftState state) Computes the mean equinoctial elements rates dai / dt.
List<ShortPeriodTerms>	initialize(AuxiliaryElements aux, boolean meanOnly) Performs initialization prior to propagation for the current force model.
void	initializeStep(AuxiliaryElements aux) Performs initialization at each integration step for the current force model.
void	registerAttitudeProvider(AttitudeProvider provider) Register an attitude provider.
void	updateShortPeriodTerms(SpacecraftState... meanStates) Update the short period terms.

Method Detail

initialize

List<ShortPeriodTerms> initialize(AuxiliaryElements aux,
                                  boolean meanOnly)
                           throws OrekitException

Performs initialization prior to propagation for the current force model.

This method aims at being called at the very beginning of a propagation.

Parameters:

aux - auxiliary elements related to the current orbit

meanOnly - only mean elements are used during the propagation

Returns:

a list of objects that will hold short period terms (the objects are also retained by the force model, which will update them during propagation)

Throws:

OrekitException - if some specific error occurs

initializeStep

void initializeStep(AuxiliaryElements aux)
             throws OrekitException

Performs initialization at each integration step for the current force model.

This method aims at being called before mean elements rates computation.

Parameters:

aux - auxiliary elements related to the current orbit

Throws:

OrekitException - if some specific error occurs

getMeanElementRate

double[] getMeanElementRate(SpacecraftState state)
                     throws OrekitException

Computes the mean equinoctial elements rates da_i / dt.

Parameters:

state - current state information: date, kinematics, attitude

Returns:

the mean element rates dai/dt

Throws:

OrekitException - if some specific error occurs

getEventsDetectors

EventDetector[] getEventsDetectors()

Get the discrete events related to the model.

Returns:

array of events detectors or null if the model is not related to any discrete events

registerAttitudeProvider

void registerAttitudeProvider(AttitudeProvider provider)

Register an attitude provider.

Register an attitude provider that can be used by the force model.

Parameters:

provider - the AttitudeProvider

updateShortPeriodTerms

void updateShortPeriodTerms(SpacecraftState... meanStates)
                     throws OrekitException

Update the short period terms.

The short period terms that will be updated are the ones that were returned during the call to initialize(AuxiliaryElements, boolean).

Parameters:

meanStates - mean states information: date, kinematics, attitude

Throws:

OrekitException - if some specific error occurs