gravity_field

None

Functions

central(gravitational_parameter)

Factory function for central gravity field settings object.

central_spice()

Factory function to create central gravity field settings from Spice settings.

spherical_harmonic(gravitational_parameter, …)

Factory function for creating a spherical harmonics gravity field settings object.

spherical_harmonic_triaxial_body(axis_a, …)

Factory function for spherical harmonics gravity field settings object from triaxial ellipsoid parameters.
central(gravitational_parameter: float) → tudatpy.kernel.simulation.environment_setup.gravity_field.GravityFieldSettings

Factory function for central gravity field settings object.

Factory function for settings object, defining a point-mass gravity field model with user-defined gravitational parameter. This function returns a GravityFieldSettings derived CentralGravityFieldSettings object.

Parameters

gravitational_parameter (float) – None

Returns

CentralGravityFieldSettings object defined by the provided gravitational parameter.

Return type

CentralGravityFieldSettings

central_spice() → tudatpy.kernel.simulation.environment_setup.gravity_field.GravityFieldSettings

Factory function to create central gravity field settings from Spice settings.

Factory function for settings object, defining a point-mass gravity field model with gravitational parameter from Spice. This function returns a GravityFieldSettings object of gravity field type central_spice.

Parameters

None – None

Returns

GravityFieldSettings object defined by gravitational parameters from Spice settings.

Return type

GravityFieldSettings

spherical_harmonic(gravitational_parameter: float, reference_radius: float, normalized_cosine_coefficients: numpy.ndarray[numpy.float64[m, n]], normalized_sine_coefficients: numpy.ndarray[numpy.float64[m, n]], associated_reference_frame: str) → tudatpy.kernel.simulation.environment_setup.gravity_field.GravityFieldSettings

Factory function for creating a spherical harmonics gravity field settings object.

Factory function for settings object, defining a gravity field model through spherical harmonic expansion. The associated reference frame must presently be the same frame ID as the target frame of the body’s rotation model. It represents the frame in which the spherical harmonic field is defined. Spherical harmonic coefficients used for this environment model must always be fully normalized. To normalize unnormalized spherical harmonic coefficients, see spherical_harmonics_normalization. This function returns a GravityFieldSettings derived SphericalHarmonicsGravityFieldSettings object.

Parameters

  • gravitational_parameter (float) – Gravitational parameter of gravity field.

  • reference_radius (float) – Reference radius of spherical harmonic field expansion.

  • normalized_cosine_coefficients (numpy.ndarray) – Cosine spherical harmonic coefficients (geodesy normalized). Entry (i,j) denotes coefficient at degree i and order j. As such, note that entry (0,0) of cosine coefficients should be equal to 1.

  • normalized_sine_coefficients (numpy.ndarray) – Sine spherical harmonic coefficients (geodesy normalized). Entry (i,j) denotes coefficient at degree i and order j.

  • associated_reference_frame (str) – Identifier for body-fixed reference frame with which the spherical harmonics coefficients are associated.

Returns

SphericalHarmonicsGravityFieldSettings object defined by the provided parameters.

Return type

SphericalHarmonicsGravityFieldSettings

spherical_harmonic_triaxial_body(axis_a: float, axis_b: float, axis_c: float, density: float, maximum_degree: int, maximum_order: int, associated_reference_frame: str) → tudatpy.kernel.simulation.environment_setup.gravity_field.SphericalHarmonicsGravityFieldSettings

Factory function for spherical harmonics gravity field settings object from triaxial ellipsoid parameters.

Factory function for settings object, defining a gravity field model through spherical harmonic expansion of a homogeneous triaxial ellipsoid. The constant mass distribution in the specified ellipsoid shape is expanded to obtain a spherical harmonic coefficient representation. Gravity fields from this setting object are expressed in normalized spherical harmonic coefficients. (%!) The x-, y- and z-axis of the … ABC (?). This function returns a GravityFieldSettings derived SphericalHarmonicsGravityFieldSettings object.

Parameters

  • axis_a (float) – Dimension of largest axis of triaxial ellipsoid.

  • axis_b (float) – Dimension of intermediate axis of triaxial ellipsoid.

  • axis_c (float) – Dimension of smallest axis of triaxial ellipsoid.

  • density (float) – Density of ellipsoid.

  • maximum_degree (int) – Maximum degree of spherical harmonics expansion.

  • maximum_order (int) – Maximum order of spherical harmonics expansion.

  • associated_reference_frame (str) – Identifier for body-fixed reference frame with which the spherical harmonics coefficients are associated.

Returns

SphericalHarmonicsGravityFieldSettings object defined by expansion of homogeneous triaxial ellipsoid.

Return type

SphericalHarmonicsGravityFieldSettings

Classes

class GravityFieldSettings

Base class for providing settings for automatic gravity field model creation.

This class is a functional base class for settings of gravity field models that require no information in addition to their type. Gravity field model classes requiring additional information must be created using an object derived from this class.

class CentralGravityFieldSettings

GravityFieldSettings derived class defining settings of point mass gravity field.

Derived class of GravityFieldSettings for central gravity fields, which are defined by a single gravitational parameter.

class SphericalHarmonicsGravityFieldSettings

GravityFieldSettings derived class defining settings of spherical harmonic gravity field representation.

Derived class of GravityFieldSettings for gravity fields, which are defined by a spherical harmonic gravity field representation.