org.orekit.forces.gravity.potential

Class CachedNormalizedSphericalHarmonicsProvider

java.lang.Object

org.orekit.forces.gravity.potential.CachedNormalizedSphericalHarmonicsProvider

All Implemented Interfaces:

NormalizedSphericalHarmonicsProvider, SphericalHarmonicsProvider, TideSystemProvider

public class CachedNormalizedSphericalHarmonicsProvider
extends Object
implements NormalizedSphericalHarmonicsProvider

Caching wrapper for NormalizedSphericalHarmonicsProvider.

This wrapper improves efficiency of NormalizedSphericalHarmonicsProvider by sampling the values at a user defined rate and using interpolation between samples. This is important with providers that have sub-daily frequencies and are computing intensive, such as tides fields.

Since:

6.1

Author:

Luc Maisonobe

See Also:

NormalizedSphericalHarmonicsProvider, SolidTides, TimeStampedCache

Nested Class Summary

Nested classes/interfaces inherited from interface org.orekit.forces.gravity.potential.NormalizedSphericalHarmonicsProvider

NormalizedSphericalHarmonicsProvider.NormalizedSphericalHarmonics

Constructor Summary

Constructors

Constructor and Description
CachedNormalizedSphericalHarmonicsProvider(NormalizedSphericalHarmonicsProvider rawProvider, double step, int nbPoints, int maxSlots, double maxSpan, double newSlotInterval) Simple constructor.

Method Summary

Modifier and Type	Method and Description
double	getAe() Get the value of the central body reference radius.
int	getMaxDegree() Get the maximal supported degree.
int	getMaxOrder() Get the maximal supported order.
double	getMu() Get the central body attraction coefficient.
double	getOffset(AbsoluteDate date) Get the offset from reference date for the harmonics.
AbsoluteDate	getReferenceDate() Get the reference date for the harmonics.
TideSystem	getTideSystem() Get the TideSystem used in the gravity field.
NormalizedSphericalHarmonicsProvider.NormalizedSphericalHarmonics	onDate(AbsoluteDate date) Get the normalized spherical harmonic coefficients at a specific instance in time.

Methods inherited from class java.lang.Object

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

Constructor Detail

CachedNormalizedSphericalHarmonicsProvider

public CachedNormalizedSphericalHarmonicsProvider(NormalizedSphericalHarmonicsProvider rawProvider,
                                                  double step,
                                                  int nbPoints,
                                                  int maxSlots,
                                                  double maxSpan,
                                                  double newSlotInterval)

Simple constructor.

Parameters:

rawProvider - underlying raw provider

step - time step between sample points for interpolation

nbPoints - number of points to use for interpolation, must be at least 2

maxSlots - maximum number of independent cached time slots

maxSpan - maximum duration span in seconds of one slot (can be set to Double.POSITIVE_INFINITY if desired)

newSlotInterval - time interval above which a new slot is created instead of extending an existing one

Method Detail

getMaxDegree

public int getMaxDegree()

Get the maximal supported degree.

Specified by:

getMaxDegree in interface SphericalHarmonicsProvider

Returns:

maximal supported degree

getMaxOrder

public int getMaxOrder()

Get the maximal supported order.

Specified by:

getMaxOrder in interface SphericalHarmonicsProvider

Returns:

maximal supported order

getMu

public double getMu()

Get the central body attraction coefficient.

Specified by:

getMu in interface SphericalHarmonicsProvider

Returns:

mu (m³/s²)

getAe

public double getAe()

Get the value of the central body reference radius.

Specified by:

getAe in interface SphericalHarmonicsProvider

Returns:

ae (m)

getReferenceDate

public AbsoluteDate getReferenceDate()

Get the reference date for the harmonics.

Specified by:

getReferenceDate in interface SphericalHarmonicsProvider

Returns:

reference date for the harmonics

getOffset

public double getOffset(AbsoluteDate date)

Get the offset from reference date for the harmonics.

Specified by:

getOffset in interface SphericalHarmonicsProvider

Parameters:

date - current date

Returns:

offset between current date and reference date if there is a reference date, or 0.0 if there are no reference dates (i.e. if SphericalHarmonicsProvider.getReferenceDate() returns null)

getTideSystem

public TideSystem getTideSystem()

Get the TideSystem used in the gravity field.

Specified by:

getTideSystem in interface TideSystemProvider

Returns:

tide system used in the gravity field

onDate

public NormalizedSphericalHarmonicsProvider.NormalizedSphericalHarmonics onDate(AbsoluteDate date)
                                                                         throws TimeStampedCacheException

Get the normalized spherical harmonic coefficients at a specific instance in time.

Specified by:

onDate in interface NormalizedSphericalHarmonicsProvider

Parameters:

date - of evaluation

Returns:

normalized coefficients on date.

Throws:

TimeStampedCacheException