agi.foundation.celestial

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

Class EarthGravitationalModel2008

java.lang.Object

agi.foundation.celestial.EarthGravitationalModel2008

public final class EarthGravitationalModel2008
extends Object

Provides the semimajor axis, gravitational parameter, and 2nd, 3rd, 4th, and 5th zonal harmonic coefficients for the Earth Gravitational Model of 2008 (EGM2008) according to the Journal of Geophysical Research, Vol 117, Issue B4, April 2012.

By convention, there is a sign difference between the two conventions for expressing the zonal harmonics such that the zonal harmonic coefficient has the opposite sign of the corresponding spherical harmonic coefficient.

See Also:

EarthGravitationalModel1996, WorldGeodeticSystem1984

Field Summary

Fields

Modifier and Type	Field and Description
static double	GravitationalParameter The gravitational parameter of the Earth in meters cubed per second squared as defined by the EGM2008 model.
static double	J2NormalizedValue The normalized second zonal harmonic coefficient.
static double	J2UnnormalizedValue The non-normalized second zonal harmonic coefficient.
static double	J3NormalizedValue The normalized third zonal harmonic coefficient.
static double	J3UnnormalizedValue The non-normalized third zonal harmonic coefficient.
static double	J4NormalizedValue The normalized fourth zonal harmonic coefficient.
static double	J4UnnormalizedValue The non-normalized fourth zonal harmonic coefficient.
static double	J5NormalizedValue The normalized fifth zonal harmonic coefficient.
static double	J5UnnormalizedValue The non-normalized fifth zonal harmonic coefficient.
static double	SemimajorAxis The semimajor axis of the Earth in meters as defined by the EGM2008 model.

Method Summary

Modifier and Type	Method and Description
static double	normalizationFactor(int degree, int order) The normalization factor for the spherical harmonic terms of the specified degree and order.
static double	normalize(double coefficient, int degree, int order) Computes the corresponding normalized value of an unnormalized coefficient.
static double	unnormalize(double coefficient, int degree, int order) Computes the corresponding unnormalized value of a normalized coefficient.

Methods inherited from class java.lang.Object

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

Field Detail

SemimajorAxis

public static final double SemimajorAxis

The semimajor axis of the Earth in meters as defined by the EGM2008 model.

See Also:

Constant Field Values

GravitationalParameter

public static final double GravitationalParameter

The gravitational parameter of the Earth in meters cubed per second squared as defined by the EGM2008 model.

See Also:

Constant Field Values

J2NormalizedValue

public static final double J2NormalizedValue

The normalized second zonal harmonic coefficient.

See Also:

Constant Field Values

J3NormalizedValue

public static final double J3NormalizedValue

The normalized third zonal harmonic coefficient.

See Also:

Constant Field Values

J4NormalizedValue

public static final double J4NormalizedValue

The normalized fourth zonal harmonic coefficient.

See Also:

Constant Field Values

J5NormalizedValue

public static final double J5NormalizedValue

The normalized fifth zonal harmonic coefficient.

See Also:

Constant Field Values

J2UnnormalizedValue

public static final double J2UnnormalizedValue

The non-normalized second zonal harmonic coefficient.

J3UnnormalizedValue

public static final double J3UnnormalizedValue

The non-normalized third zonal harmonic coefficient.

J4UnnormalizedValue

public static final double J4UnnormalizedValue

The non-normalized fourth zonal harmonic coefficient.

J5UnnormalizedValue

public static final double J5UnnormalizedValue

The non-normalized fifth zonal harmonic coefficient.

Method Detail

normalize

public static double normalize(double coefficient,
                               int degree,
                               int order)

Computes the corresponding normalized value of an unnormalized coefficient.

Parameters:

coefficient - The unnormalized coefficient value.

degree - The degree of the coefficient.

order - The order of the coefficient.

Returns:

The normalized value.

unnormalize

public static double unnormalize(double coefficient,
                                 int degree,
                                 int order)

Computes the corresponding unnormalized value of a normalized coefficient.

Parameters:

coefficient - The normalized coefficient value.

degree - The degree of the coefficient.

order - The order of the coefficient.

Returns:

The unnormalized value.

normalizationFactor

public static double normalizationFactor(int degree,
                                         int order)

The normalization factor for the spherical harmonic terms of the specified degree and order. The unnormalized value divided by the normalization factor yields the normalized value.

Parameters:

degree - The degree.

order - The order.

Returns:

The normalization factor.