Package org.orekit.propagation.semianalytical.dsst.forces

Interface DSSTForceModel

All Superinterfaces:

EventDetectorsProvider, ParameterDriversProvider

All Known Implementing Classes:

AbstractGaussianContribution, DSSTAtmosphericDrag, DSSTJ2SquaredClosedForm, DSSTNewtonianAttraction, DSSTSolarRadiationPressure, DSSTTesseral, DSSTThirdBody, DSSTZonal

public interface DSSTForceModel
extends ParameterDriversProvider, EventDetectorsProvider

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 initializeShortPeriodTerms(AuxiliaryElements, PropagationType, double[]) method allowing preliminary computation such as truncation if needed.

Then the propagator will call at each step:

1. the getMeanElementRate(SpacecraftState, AuxiliaryElements, double[]) 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.
2. the updateShortPeriodTerms(double[], SpacecraftState...) method, if osculating parameters are desired, on a sample of points within the last step.

Author:

Romain Di Constanzo, Pascal Parraud

Field Summary

Fields inherited from interface org.orekit.propagation.events.EventDetectorsProvider

DATATION_ACCURACY

Method Summary

Modifier and Type	Method	Description
default double[]	extractParameters(double[] parameters, AbsoluteDate date)	Extract the proper parameter drivers' values from the array in input of the updateShortPeriodTerms method.
default <T extends CalculusFieldElement<T>> T[]	extractParameters(T[] parameters, FieldAbsoluteDate<T> date)	Extract the proper parameter drivers' values from the array in input of the updateShortPeriodTerms method.
default Stream<EventDetector>	getEventDetectors()	Get the discrete events related to the model.
default <T extends CalculusFieldElement<T>> Stream<FieldEventDetector<T>>	getFieldEventDetectors(Field<T> field)	Get the discrete events related to the model.
<T extends CalculusFieldElement<T>> T[]	getMeanElementRate(FieldSpacecraftState<T> state, FieldAuxiliaryElements<T> auxiliaryElements, T[] parameters)	Computes the mean equinoctial elements rates dai / dt.
double[]	getMeanElementRate(SpacecraftState state, AuxiliaryElements auxiliaryElements, double[] parameters)	Computes the mean equinoctial elements rates dai / dt.
default <T extends CalculusFieldElement<T>> void	init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target)	Initialize the force model at the start of propagation.
default void	init(SpacecraftState initialState, AbsoluteDate target)	Initialize the force model at the start of propagation.
List<ShortPeriodTerms>	initializeShortPeriodTerms(AuxiliaryElements auxiliaryElements, PropagationType type, double[] parameters)	Performs initialization prior to propagation for the current force model.
<T extends CalculusFieldElement<T>> List<FieldShortPeriodTerms<T>>	initializeShortPeriodTerms(FieldAuxiliaryElements<T> auxiliaryElements, PropagationType type, T[] parameters)	Performs initialization prior to propagation for the current force model.
void	registerAttitudeProvider(AttitudeProvider provider)	Register an attitude provider.
void	updateShortPeriodTerms(double[] parameters, SpacecraftState... meanStates)	Update the short period terms.
<T extends CalculusFieldElement<T>> void	updateShortPeriodTerms(T[] parameters, FieldSpacecraftState<T>... meanStates)	Update the short period terms.

Methods inherited from interface org.orekit.propagation.events.EventDetectorsProvider

getDateDetector, getEventDetectors, getFieldDateDetector, getFieldEventDetectors

Methods inherited from interface org.orekit.utils.ParameterDriversProvider

getNbParametersDriversValue, getParameterDriver, getParameters, getParameters, getParameters, getParameters, getParametersAllValues, getParametersAllValues, getParametersDrivers, isSupported

Method Detail

init

default void init(SpacecraftState initialState,
                  AbsoluteDate target)

Initialize the force model at the start of propagation.

The default implementation of this method does nothing.

Parameters:

initialState - spacecraft state at the start of propagation.

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

Since:

11.0

init

default <T extends CalculusFieldElement<T>> void init(FieldSpacecraftState<T> initialState,
                                                      FieldAbsoluteDate<T> target)

Initialize the force model at the start of propagation.

The default implementation of this method does nothing.

Type Parameters:

T - type of the elements

Parameters:

initialState - spacecraft state at the start of propagation.

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

Since:

11.1

getEventDetectors

default Stream<EventDetector> getEventDetectors()

Get the discrete events related to the model.

This method is not intended to be called several time, only once by a propagator, as it has the side effect of rebuilding the events detectors when called.

Specified by:

getEventDetectors in interface EventDetectorsProvider

Returns:

stream of event detectors

getFieldEventDetectors

default <T extends CalculusFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventDetectors(Field<T> field)

Get the discrete events related to the model.

This method is not intended to be called several time, only once by a propagator, as it has the side effect of rebuilding the events detectors when called.

Specified by:

getFieldEventDetectors in interface EventDetectorsProvider

Type Parameters:

T - extends CalculusFieldElement<T>

Parameters:

field - field to which the state belongs

Returns:

stream of event detectors

initializeShortPeriodTerms

List<ShortPeriodTerms> initializeShortPeriodTerms(AuxiliaryElements auxiliaryElements,
                                                  PropagationType type,
                                                  double[] parameters)

Performs initialization prior to propagation for the current force model.

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

Parameters:

auxiliaryElements - auxiliary elements related to the current orbit

type - type of the elements used during the propagation

parameters - values of the force model parameters for specific date (1 value only per parameter driver) obtained for example by calling ParameterDriversProvider.getParameters(AbsoluteDate) on force model.

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)

initializeShortPeriodTerms

<T extends CalculusFieldElement<T>> List<FieldShortPeriodTerms<T>> initializeShortPeriodTerms(FieldAuxiliaryElements<T> auxiliaryElements,
                                                                                              PropagationType type,
                                                                                              T[] parameters)

Performs initialization prior to propagation for the current force model.

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

Type Parameters:

T - type of the elements

Parameters:

auxiliaryElements - auxiliary elements related to the current orbit

type - type of the elements used during the propagation

parameters - values of the force model parameters for specific date (1 value only per parameter driver) obtained for example by calling ParameterDriversProvider.getParameters(AbsoluteDate) on force model or AbstractGradientConverter.getParametersAtStateDate(FieldSpacecraftState, ParameterDriversProvider) on gradient converter.

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)

extractParameters

default double[] extractParameters(double[] parameters,
                                   AbsoluteDate date)

Extract the proper parameter drivers' values from the array in input of the updateShortPeriodTerms method. Parameters are filtered given an input date.

Parameters:

parameters - the input parameters array containing all span values of all drivers from which the parameter values at date date wants to be extracted

date - the date

Returns:

the parameters given the date

extractParameters

default <T extends CalculusFieldElement<T>> T[] extractParameters(T[] parameters,
                                                                  FieldAbsoluteDate<T> date)

Extract the proper parameter drivers' values from the array in input of the updateShortPeriodTerms method. Parameters are filtered given an input date.

Type Parameters:

T - extends CalculusFieldElement

Parameters:

parameters - the input parameters array containing all span values of all drivers from which the parameter values at date date wants to be extracted

date - the date

Returns:

the parameters given the date

getMeanElementRate

double[] getMeanElementRate(SpacecraftState state,
                            AuxiliaryElements auxiliaryElements,
                            double[] parameters)

Computes the mean equinoctial elements rates da_i / dt.

Parameters:

state - current state information: date, kinematics, attitude

auxiliaryElements - auxiliary elements related to the current orbit

parameters - values of the force model parameters at state date (only 1 span for each parameter driver) obtained for example by calling ParameterDriversProvider.getParameters(AbsoluteDate) on force model.

Returns:

the mean element rates dai/dt

getMeanElementRate

<T extends CalculusFieldElement<T>> T[] getMeanElementRate(FieldSpacecraftState<T> state,
                                                           FieldAuxiliaryElements<T> auxiliaryElements,
                                                           T[] parameters)

Computes the mean equinoctial elements rates da_i / dt.

Type Parameters:

T - type of the elements

Parameters:

state - current state information: date, kinematics, attitude

auxiliaryElements - auxiliary elements related to the current orbit

parameters - values of the force model parameters at state date (only 1 span for each parameter driver) obtained for example by calling ParameterDriversProvider.getParameters(Field, FieldAbsoluteDate) on force model or AbstractGradientConverter.getParametersAtStateDate(FieldSpacecraftState, ParameterDriversProvider) on gradient converter.

Returns:

the mean element rates dai/dt

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(double[] parameters,
                            SpacecraftState... meanStates)

Update the short period terms.

The short period terms that will be updated are the ones that were returned during the call to initializeShortPeriodTerms(AuxiliaryElements, PropagationType, double[]).

Parameters:

parameters - values of the force model parameters (all span values for each parameters) obtained for example by calling ParameterDriversProvider.getParametersAllValues() on force model. The extract parameter method extractParameters(double[], AbsoluteDate) is called in the method to select the right parameter corresponding to the mean state date.

meanStates - mean states information: date, kinematics, attitude

updateShortPeriodTerms

<T extends CalculusFieldElement<T>> void updateShortPeriodTerms(T[] parameters,
                                                                FieldSpacecraftState<T>... meanStates)

Update the short period terms.

The short period terms that will be updated are the ones that were returned during the call to initializeShortPeriodTerms(AuxiliaryElements, PropagationType, double[]).

Type Parameters:

T - type of the elements

Parameters:

parameters - values of the force model parameters (all span values for each parameters) obtained for example by calling ParameterDriversProvider.getParametersAllValues(Field) on force model or AbstractGradientConverter.getParameters(FieldSpacecraftState, ParameterDriversProvider) on gradient converter. The extract parameter method extractParameters(CalculusFieldElement[], FieldAbsoluteDate) is called in the method to select the right parameter.

meanStates - mean states information: date, kinematics, attitude