Package 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

Constructor Summary

Constructors

Constructor	Description
DSSTZonal(UnnormalizedSphericalHarmonicsProvider provider, int maxDegreeShortPeriodics, int maxEccPowShortPeriodics, int maxFrequencyShortPeriodics)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
EventDetector[]	getEventsDetectors()	Get the discrete events related to the model.
double[]	getMeanElementRate(SpacecraftState spacecraftState)	Computes the mean equinoctial elements rates dai / dt.
UnnormalizedSphericalHarmonicsProvider	getProvider()	Get the spherical harmonics provider.
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 attitudeProvider)	Register an attitude provider.
void	updateShortPeriodTerms(SpacecraftState... meanStates)	Update the short period terms.

Methods inherited from class java.lang.Object

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

Constructor Detail

DSSTZonal

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

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)

Throws:

OrekitException - if degrees or powers are out of range

Since:

7.2

Method Detail

getProvider

public UnnormalizedSphericalHarmonicsProvider getProvider()

Get the spherical harmonics provider.

Returns:

the spherical harmonics provider

initialize

public 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.

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:

initialize in interface DSSTForceModel

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

public 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.

Specified by:

initializeStep in interface DSSTForceModel

Parameters:

aux - auxiliary elements related to the current orbit

Throws:

OrekitException - if some specific error occurs

getMeanElementRate

public double[] getMeanElementRate(SpacecraftState spacecraftState)
                            throws OrekitException

Computes the mean equinoctial elements rates da_i / dt.

Specified by:

getMeanElementRate in interface DSSTForceModel

Parameters:

spacecraftState - current state information: date, kinematics, attitude

Returns:

the mean element rates dai/dt

Throws:

OrekitException - if some specific error occurs

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

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(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 DSSTForceModel.initialize(AuxiliaryElements, boolean).

Specified by:

updateShortPeriodTerms in interface DSSTForceModel

Parameters:

meanStates - mean states information: date, kinematics, attitude

Throws:

OrekitException - if some specific error occurs