org.orekit.propagation.semianalytical.dsst.forces

Class DSSTZonal

java.lang.Object

org.orekit.propagation.semianalytical.dsst.forces.DSSTZonal

All Implemented Interfaces:

DSSTForceModel

public class DSSTZonal
extends Object
implements DSSTForceModel

Zonal contribution to the central body gravitational perturbation.

Author:

Romain Di Costanzo, Pascal Parraud, Bryan Cazabonne (field translation)

Field Summary

Fields

Modifier and Type	Field and Description
static String	SHORT_PERIOD_PREFIX Name of the prefix for short period coefficients keys.

Constructor Summary

Constructors

Constructor and Description
DSSTZonal(UnnormalizedSphericalHarmonicsProvider provider) Constructor with default reference values.
DSSTZonal(UnnormalizedSphericalHarmonicsProvider provider, int maxDegreeShortPeriodics, int maxEccPowShortPeriodics, int maxFrequencyShortPeriodics) Simple constructor.

Method Summary

Modifier and Type	Method and Description
EventDetector[]	getEventsDetectors() Get the discrete events related to the model.
<T extends CalculusFieldElement<T>> FieldEventDetector<T>[]	getFieldEventsDetectors(Field<T> field) Get the discrete events related to the model.
<T extends CalculusFieldElement<T>> T[]	getMeanElementRate(FieldSpacecraftState<T> spacecraftState, FieldAuxiliaryElements<T> auxiliaryElements, T[] parameters) Computes the mean equinoctial elements rates dai / dt.
double[]	getMeanElementRate(SpacecraftState spacecraftState, AuxiliaryElements auxiliaryElements, double[] parameters) Computes the mean equinoctial elements rates dai / dt.
List<ParameterDriver>	getParametersDrivers() Get the drivers for force model parameters.
UnnormalizedSphericalHarmonicsProvider	getProvider() Get the spherical harmonics provider.
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 attitudeProvider) 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 class java.lang.Object

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

Methods inherited from interface org.orekit.propagation.semianalytical.dsst.forces.DSSTForceModel

getParameters, getParameters, init, init

Field Detail

SHORT_PERIOD_PREFIX

public static final String SHORT_PERIOD_PREFIX

Name of the prefix for short period coefficients keys.

See Also:

Constant Field Values

Constructor Detail

DSSTZonal

public DSSTZonal(UnnormalizedSphericalHarmonicsProvider provider)

Constructor with default reference values.

When this constructor is used, maximum allowed values are used for the short periodic coefficients:

• maxDegreeShortPeriodics is set to provider.getMaxDegree()
• maxEccPowShortPeriodics is set to min(provider.getMaxDegree() - 1, 4). This parameter should not exceed 4 as higher values will exceed computer capacity
• maxFrequencyShortPeriodics is set to 2 * provider.getMaxDegree() + 1

Parameters:

provider - provider for spherical harmonics

Since:

10.1

DSSTZonal

public DSSTZonal(UnnormalizedSphericalHarmonicsProvider provider,
                 int maxDegreeShortPeriodics,
                 int maxEccPowShortPeriodics,
                 int maxFrequencyShortPeriodics)

Simple constructor.

Parameters:

provider - provider for spherical harmonics

maxDegreeShortPeriodics - maximum degree to consider for short periodics zonal harmonics potential (must be between 2 and provider.getMaxDegree())

maxEccPowShortPeriodics - maximum power of the eccentricity to be used in short periodic computations (must be between 0 and maxDegreeShortPeriodics - 1, but should typically not exceed 4 as higher values will exceed computer capacity)

maxFrequencyShortPeriodics - maximum frequency in true longitude for short periodic computations (must be between 1 and 2 * maxDegreeShortPeriodics + 1)

Since:

7.2

Method Detail

getProvider

public UnnormalizedSphericalHarmonicsProvider getProvider()

Get the spherical harmonics provider.

Returns:

the spherical harmonics provider

initializeShortPeriodTerms

public 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.

Computes the highest power of the eccentricity to appear in the truncated analytical power series expansion.

This method computes the upper value for the central body potential and determines the maximal power for the eccentricity producing potential terms bigger than a defined tolerance.

Specified by:

initializeShortPeriodTerms in interface DSSTForceModel

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

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

public <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.

Computes the highest power of the eccentricity to appear in the truncated analytical power series expansion.

This method computes the upper value for the central body potential and determines the maximal power for the eccentricity producing potential terms bigger than a defined tolerance.

Specified by:

initializeShortPeriodTerms in interface DSSTForceModel

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

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)

getMeanElementRate

public double[] getMeanElementRate(SpacecraftState spacecraftState,
                                   AuxiliaryElements auxiliaryElements,
                                   double[] parameters)

Computes the mean equinoctial elements rates da_i / dt.

Specified by:

getMeanElementRate in interface DSSTForceModel

Parameters:

spacecraftState - current state information: date, kinematics, attitude

auxiliaryElements - auxiliary elements related to the current orbit

parameters - values of the force model parameters

Returns:

the mean element rates dai/dt

getMeanElementRate

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

Computes the mean equinoctial elements rates da_i / dt.

Specified by:

getMeanElementRate in interface DSSTForceModel

Type Parameters:

T - type of the elements

Parameters:

spacecraftState - current state information: date, kinematics, attitude

auxiliaryElements - auxiliary elements related to the current orbit

parameters - values of the force model parameters

Returns:

the mean element rates dai/dt

getEventsDetectors

public EventDetector[] getEventsDetectors()

Get the discrete events related to the model.

Specified by:

getEventsDetectors in interface DSSTForceModel

Returns:

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

getFieldEventsDetectors

public <T extends CalculusFieldElement<T>> FieldEventDetector<T>[] getFieldEventsDetectors(Field<T> field)

Get the discrete events related to the model.

Specified by:

getFieldEventsDetectors in interface DSSTForceModel

Type Parameters:

T - type of the elements

Parameters:

field - field used by default

Returns:

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

registerAttitudeProvider

public void registerAttitudeProvider(AttitudeProvider attitudeProvider)

Register an attitude provider.

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

Specified by:

registerAttitudeProvider in interface DSSTForceModel

Parameters:

attitudeProvider - the AttitudeProvider

updateShortPeriodTerms

public 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 DSSTForceModel.initializeShortPeriodTerms(AuxiliaryElements, PropagationType, double[]).

Specified by:

updateShortPeriodTerms in interface DSSTForceModel

Parameters:

parameters - values of the force model parameters

meanStates - mean states information: date, kinematics, attitude

updateShortPeriodTerms

public <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 DSSTForceModel.initializeShortPeriodTerms(AuxiliaryElements, PropagationType, double[]).

Specified by:

updateShortPeriodTerms in interface DSSTForceModel

Type Parameters:

T - type of the elements

Parameters:

parameters - values of the force model parameters

meanStates - mean states information: date, kinematics, attitude

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Get the drivers for force model parameters.

Specified by:

getParametersDrivers in interface DSSTForceModel

Returns:

drivers for force model parameters