agi.foundation.celestial

(agi.foundation.orbitpropagation-2024r2.jar)

Class SphericalHarmonicGravityModel

java.lang.Object

agi.foundation.celestial.SphericalHarmonicGravityModel

public class SphericalHarmonicGravityModel
extends Object

Contains the coefficient data for a gravity model, either specified upon construction or read in from a file. This type is passed to a SphericalHarmonicGravityField which down selects to the desired subset of this full model, and sets other configuration options. The field is then used by SphericalHarmonicGravity in order to calculate the gravitational force.

Constructor Summary

Constructors

Constructor and Description
SphericalHarmonicGravityModel() Initializes a new instance.
SphericalHarmonicGravityModel(String modelName, String centralBodyName, double gravitationalParameter, double referenceDistance, double[] zonalCoefficients, double[][] cosineCoefficients, double[][] sineCoefficients, boolean normalized, boolean includesPermanentTides) Initializes a new instance.
SphericalHarmonicGravityModel(String modelName, String centralBodyName, double gravitationalParameter, double referenceDistance, double[] zonalCoefficients, double[][] cosineCoefficients, double[][] sineCoefficients, boolean normalized, boolean includesPermanentTides, SphericalHarmonicGravitySecularVariations secularVariations) Initializes a new instance.

Method Summary

Modifier and Type	Method and Description
static SphericalHarmonicCoefficients	createEarthPermanentTideCoefficients() Creates a set of the default IERS 2003 permanent tide coefficients for Earth.
String	getCentralBodyName() Gets the name of the central body described by the model.
double[][]	getCosineCoefficients() Gets the list of this model's Cosine coefficients (m= [1, L])
int	getFileDegree() Gets the maximum degree of the gravitation coefficients defined by the .grv file.
int	getFileOrder() Gets the maximum order of the gravitation coefficients defined by the .grv file.
double	getGravitationalParameter() Gets the gravitational parameter of the central body.
boolean	getIncludesPermanentTides() Gets a value indicating whether the coefficients of the gravity model include permanent tides.
String	getModelName() Gets the name of the gravity model being used.
boolean	getNormalized() Gets a value indicating whether the coefficients of the gravity model are normalized.
double	getReferenceDistance() Gets the reference distance of the central body.
SphericalHarmonicGravitySecularVariations	getSecularVariations() Gets the linear model for the secular variations of this gravity model.
double[][]	getSineCoefficients() Gets the list of this model's Sine coefficients (m= [1, L])
double[]	getZonalCoefficients() Gets the list of this model's zonal coefficients (cosine coefficients for m=0).
static SphericalHarmonicGravityModel	readFrom(BufferedReader reader) Reads the gravity model information in from a BufferedReader and returns a SphericalHarmonicGravityModel
static SphericalHarmonicGravityModel	readFrom(String fileName) Reads the gravity model information in from a file (most likely a .grv) and returns a SphericalHarmonicGravityModel.
void	setCentralBodyName(String value) Sets the name of the central body described by the model.
void	setFileDegree(int value) Sets the maximum degree of the gravitation coefficients defined by the .grv file.
void	setFileOrder(int value) Sets the maximum order of the gravitation coefficients defined by the .grv file.
void	setGravitationalParameter(double value) Sets the gravitational parameter of the central body.
void	setIncludesPermanentTides(boolean value) Sets a value indicating whether the coefficients of the gravity model include permanent tides.
void	setModelName(String value) Sets the name of the gravity model being used.
void	setNormalized(boolean value) Sets a value indicating whether the coefficients of the gravity model are normalized.
void	setReferenceDistance(double value) Sets the reference distance of the central body.
void	setSecularVariations(SphericalHarmonicGravitySecularVariations value) Sets the linear model for the secular variations of this gravity model.
SphericalHarmonicGravityModel	withoutEarthPermanentTides() Removes the IERS2003 Earth permanent tide contributions so that a time-varying tide model can be applied instead.
SphericalHarmonicGravityModel	withoutPermanentTides(SphericalHarmonicCoefficients permanentTideCoefficients) Removes the permanent tide contributions so that a time-varying tide model can be applied instead.

Methods inherited from class java.lang.Object

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

Constructor Detail

SphericalHarmonicGravityModel

public SphericalHarmonicGravityModel()

Initializes a new instance.

SphericalHarmonicGravityModel

public SphericalHarmonicGravityModel(String modelName,
                                     String centralBodyName,
                                     double gravitationalParameter,
                                     double referenceDistance,
                                     @Nonnull
                                     double[] zonalCoefficients,
                                     @Nonnull
                                     double[][] cosineCoefficients,
                                     @Nonnull
                                     double[][] sineCoefficients,
                                     boolean normalized,
                                     boolean includesPermanentTides)

Initializes a new instance.

This constructor will set the SecularVariations (get / set) to null.

Parameters:

modelName - The name of the gravitational model.

centralBodyName - The name of the central body.

gravitationalParameter - The gravitational parameter described by the central body.

referenceDistance - The reference distance of the body.

zonalCoefficients - The zonal gravity coefficients.

cosineCoefficients - The cosine gravity coefficients.

sineCoefficients - The sine gravity coefficients.

normalized - The flag representing whether the coefficients are normalized.

includesPermanentTides - The flag representing whether the coefficients include the effect of permanent tides.

SphericalHarmonicGravityModel

public SphericalHarmonicGravityModel(String modelName,
                                     String centralBodyName,
                                     double gravitationalParameter,
                                     double referenceDistance,
                                     @Nonnull
                                     double[] zonalCoefficients,
                                     @Nonnull
                                     double[][] cosineCoefficients,
                                     @Nonnull
                                     double[][] sineCoefficients,
                                     boolean normalized,
                                     boolean includesPermanentTides,
                                     @Nullable
                                     SphericalHarmonicGravitySecularVariations secularVariations)

Initializes a new instance.

Parameters:

modelName - The name of the gravitational model.

centralBodyName - The name of the central body.

gravitationalParameter - The gravitational parameter described by the central body.

referenceDistance - The reference distance of the body.

zonalCoefficients - The zonal gravity coefficients.

cosineCoefficients - The cosine gravity coefficients.

sineCoefficients - The sine gravity coefficients.

normalized - The flag representing whether the coefficients are normalized.

includesPermanentTides - The flag representing whether the coefficients include the effect of permanent tides.

secularVariations - A linear model for the secular variations of this gravity model. null if the model does not contain secular variations.

Method Detail

readFrom

@Nonnull
public static SphericalHarmonicGravityModel readFrom(@Nonnull
                                                               String fileName)

Reads the gravity model information in from a file (most likely a .grv) and returns a SphericalHarmonicGravityModel.

If the .grv file contains uncommented SecularVariation RefEpochTDT and LinearRate lines, the returned gravity model will include secular variations by default. If secular variations are not desired, SecularVariations (get / set) must be manually set to null.

Parameters:

fileName - Name of the gravity file from which to read.

Returns:

The gravity model described in the file.

Throws:

ArgumentNullException - Thrown when fileName is null.

readFrom

@Nonnull
public static SphericalHarmonicGravityModel readFrom(@Nonnull
                                                               BufferedReader reader)

Reads the gravity model information in from a BufferedReader and returns a SphericalHarmonicGravityModel

If the .grv file contains uncommented SecularVariation RefEpochTDT and LinearRate lines, the returned gravity model will include secular variations by default. If secular variations are not desired, SecularVariations (get / set) must be manually set to null.

Parameters:

reader - BufferedReader for the .grv file to read.

Returns:

The gravity model described in the file.

Throws:

ArgumentNullException - Thrown when reader is null.

withoutEarthPermanentTides

@Nonnull
public final SphericalHarmonicGravityModel withoutEarthPermanentTides()

Removes the IERS2003 Earth permanent tide contributions so that a time-varying tide model can be applied instead.

Returns:

A copy of the original model that has the contributions of the IERS2003 Earth permanent tide subtracted from the gravity coefficients.

Throws:

PropertyInvalidException - Thrown when CentralBodyName (get / set) is not Earth.

withoutPermanentTides

@Nonnull
public final SphericalHarmonicGravityModel withoutPermanentTides(@Nonnull
                                                                           SphericalHarmonicCoefficients permanentTideCoefficients)

Removes the permanent tide contributions so that a time-varying tide model can be applied instead.

Parameters:

permanentTideCoefficients - The permanent tide contribution that must be subtracted from a model that includes permanent tides.

Returns:

A copy of the original model that has the contributions of the permanent tide subtracted from the gravity coefficients.

Throws:

ArgumentNullException - Thrown when permanentTideCoefficients is null.

createEarthPermanentTideCoefficients

@Nonnull
public static SphericalHarmonicCoefficients createEarthPermanentTideCoefficients()

Creates a set of the default IERS 2003 permanent tide coefficients for Earth. These are identical to those created by the default constructor of PermanentSolidTideModel.

Returns:

The default IERS 2003 permanent tide coefficients for Earth.

getModelName

public final String getModelName()

Gets the name of the gravity model being used.

setModelName

public final void setModelName(String value)

Sets the name of the gravity model being used.

getCentralBodyName

public final String getCentralBodyName()

Gets the name of the central body described by the model.

setCentralBodyName

public final void setCentralBodyName(String value)

Sets the name of the central body described by the model.

getFileDegree

public final int getFileDegree()

Gets the maximum degree of the gravitation coefficients defined by the .grv file.

setFileDegree

public final void setFileDegree(int value)

Sets the maximum degree of the gravitation coefficients defined by the .grv file.

getFileOrder

public final int getFileOrder()

Gets the maximum order of the gravitation coefficients defined by the .grv file.

setFileOrder

public final void setFileOrder(int value)

Sets the maximum order of the gravitation coefficients defined by the .grv file.

getGravitationalParameter

public final double getGravitationalParameter()

Gets the gravitational parameter of the central body.

setGravitationalParameter

public final void setGravitationalParameter(double value)

Sets the gravitational parameter of the central body.

getReferenceDistance

public final double getReferenceDistance()

Gets the reference distance of the central body.

setReferenceDistance

public final void setReferenceDistance(double value)

Sets the reference distance of the central body.

getNormalized

public final boolean getNormalized()

Gets a value indicating whether the coefficients of the gravity model are normalized.

setNormalized

public final void setNormalized(boolean value)

Sets a value indicating whether the coefficients of the gravity model are normalized.

getIncludesPermanentTides

public final boolean getIncludesPermanentTides()

Gets a value indicating whether the coefficients of the gravity model include permanent tides.

setIncludesPermanentTides

public final void setIncludesPermanentTides(boolean value)

Sets a value indicating whether the coefficients of the gravity model include permanent tides.

getZonalCoefficients

public final double[] getZonalCoefficients()

Gets the list of this model's zonal coefficients (cosine coefficients for m=0).

getCosineCoefficients

public final double[][] getCosineCoefficients()

Gets the list of this model's Cosine coefficients (m= [1, L])

getSineCoefficients

public final double[][] getSineCoefficients()

Gets the list of this model's Sine coefficients (m= [1, L])

getSecularVariations

@Nullable
public final SphericalHarmonicGravitySecularVariations getSecularVariations()

Gets the linear model for the secular variations of this gravity model.

If null, then secular variations will not be applied to the gravity field.

setSecularVariations

public final void setSecularVariations(@Nullable
                                       SphericalHarmonicGravitySecularVariations value)

Sets the linear model for the secular variations of this gravity model.

If null, then secular variations will not be applied to the gravity field.