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 and 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 org.hipparchus.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 org.hipparchus.CalculusFieldElement<T>> Stream<FieldEventDetector<T>>	getFieldEventDetectors(org.hipparchus.Field<T> field) Get the discrete events related to the model.
<T extends org.hipparchus.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 org.hipparchus.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 org.hipparchus.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 org.hipparchus.CalculusFieldElement<T>> void	updateShortPeriodTerms(T[] parameters, FieldSpacecraftState<T>... meanStates) Update the short period terms.

Methods inherited from interface org.orekit.utils.ParameterDriversProvider

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

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

getEventDetectors, getFieldEventDetectors

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 org.hipparchus.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 org.hipparchus.CalculusFieldElement<T>> Stream<FieldEventDetector<T>> getFieldEventDetectors(org.hipparchus.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 org.hipparchus.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 org.hipparchus.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 org.hipparchus.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 org.hipparchus.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