rotation_model

None

Functions

simple(base_frame, target_frame, …)	Factory function for creating simple rotation model settings.
simple_from_spice(base_frame, target_frame, …)	Factory function for creating simple rotation model settings using initial orientation and rotaton rates from Spice.
synchronous(central_body_name, base_frame, …)	Factory function for creating synchronous rotational ephemeris settings.
spice(base_frame, target_frame)	Factory function for creating rotation model settings from the Spice interface.
gcrs_to_itrs(precession_nutation_theory, …)	Factory function for creating high-accuracy Earth rotation model settings.
constant(base_frame, target_frame, …)	Factory function for creating simple rotation model settings for target-frames with constant orientation.

simple(base_frame: str, target_frame: str, initial_orientation: numpy.ndarray[numpy.float64[3, 3]], initial_time: float, rotation_rate: float) → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating simple rotation model settings.

Factory function for settings object, defining a basic rotation model with constant orientation of the rotation axis and constant rotation rate about this axis. Rotation from original (inertial) to target (body-fixed) frame at some reference time initial_time is defined by the initial_orientation rotation matrix. Rotation about the body-fixed z-axis is defined by the rotation_rate float variable (in rad/s). This function creates an instance of a RotationModelSettings derived simpleRotationModelSettings object.

Parameters

• base_frame (str) – Base frame of rotation model.

• target_frame (str) – Target frame of rotation model.

• initial_orientation (numpy.ndarray) – Orientation of target frame in base frame at initial time.

• initial_time (float) – Initial time (reference epoch for rotation matrices).

• rotation_rate (float) – Constant rotation rate [rad/s] about rotational axis.

Returns

Simple rotation model settings object (derived from RotationModelSettings base class).

Return type

SimpleRotationModelSettings

simple_from_spice(base_frame: str, target_frame: str, target_frame_spice: str, initial_time: float) → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating simple rotation model settings using initial orientation and rotaton rates from Spice.

Factory function for settings object, defining a simple rotation model with the added functionality that the initial orientation and rotation rate are extracted from Spice, as opposed to provided manually. Note that only the initial orientation and rotation rate ( at the time defined by initial_time ) are extracted from Spice. The distinction between the two target frame inputs is the following

• the target_frame parameter is the name of frame that Tudat assigns to the body-fixed frame

• the target_frame_spice is the name of the frame in Spice for which the initial orientation and rotation rate are extracted.

This function creates an instance of a RotationModelSettings derived simpleRotationModelSettings object.

Parameters

• base_frame (str) – Base frame of rotation model.

• target_frame (str) – Target frame of rotation model.

• target_frame_spice (str) – Spice reference of target frame.

• initial_time (float) – Initial time (reference epoch for rotation matrices).

Returns

Simple rotation model settings object (derived from RotationModelSettings base class) with target frame info inferred from Spice.

Return type

SimpleRotationModelSettings

synchronous(central_body_name: str, base_frame: str, target_frame: str) → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating synchronous rotational ephemeris settings.

Factory function for settings object, defining a synchronous rotation model where rotation of a body is defined from its relative orbit w.r.t. some central body. Specifically - the body-fixed x-axis is always pointing towards the central body - the body-fixed z-axis is always perpendicular to the orbital plane (along the direction of .. math:: mathbf{x} cross mathbf{v} ) - the body-fixed y-axis completes the right-handed reference frame

Such a model can be useful for, for instance, approximate rotation of tidally locked natural satellites or nadir-pointing spacraft. This function creates an instance of a RotationModelSettings derived SynchronousRotationModelSettings object.

Parameters

• central_body_name (str) – Base frame of rotation model.

• base_frame (str) – Base frame of rotation model.

• target_frame (str) – Spice reference of target frame.

Returns

Synchonous rotation model settings object (derived from RotationModelSettings base class).

Return type

SynchronousRotationModelSettings

spice(base_frame: str, target_frame: str) → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating rotation model settings from the Spice interface.

Factory function for settings object, defining a rotation model directly (and entirely) from Spice interface. This function creates an instance of a RotationModelSettings object.

Parameters

• base_frame (str) – Base frame of rotation model.

• target_frame (str) – Target frame of rotation model.

Returns

Rotation model settings object inferred from Spice rotational model.

Return type

RotationModelSettings

gcrs_to_itrs(precession_nutation_theory: tudatpy.kernel.simulation.environment_setup.rotation_model.IAUConventions = <IAUConventions.iau_2006: 2>, base_frame: str = 'GCRS') → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating high-accuracy Earth rotation model settings.

Factory function for settings object, defining high-accuracy Earth rotation model according to the IERS 2010 Conventions. This settings class has various options to deviate from the default settings, typical applications will use default. Note that for this model the original frame must be J2000 or GCRS (in the case of the former, the frame bias between GCRS and J2000 is automatically corrected for). The target frame (e.g. body-fixed frame) name is ITRS. The precession-nutation theory may be iau_2000a / iau_2000b or iau_2006, as implemented in the SOFA toolbox. Alternative options to modify the input (not shown above) include the EOP correction file, input time scale, short period UT1 and polar motion variations. The target frame (e.g. body-fixed frame) name is ITRS. This function creates an instance of a RotationModelSettings derived gcrsToItrsRotationModelSettings object.

Parameters

• precession_nutation_theory (default=tba::iau_2006) – Setting theory for modelling Earth nutation.

• base_frame (str, default='GCRS') – Base frame of rotation model

Returns

High-accuracy Earth rotation model settings object (derived from RotationModelSettings base class).

Return type

GcrsToItrsRotationModelSettings

constant(base_frame: str, target_frame: str, initial_orientation: numpy.ndarray[numpy.float64[3, 3]]) → tudatpy.kernel.simulation.environment_setup.rotation_model.RotationModelSettings

Factory function for creating simple rotation model settings for target-frames with constant orientation.

Factory function for settings object, defining simple rotation model setting objects with constant rotation matrix. These model settings are for target frames which do not have a rotational rate in the base frame and are fully defined by their initial orientation. This function creates an instance of a RotationModelSettings derived SimpleRotationModelSettings object.

Parameters

• base_frame (str) – Base frame of rotation model.

• target_frame (str) – Target frame of rotation model.

• initial_orientation (numpy.ndarray) – Orientation of target frame in base frame at initial time (constant throughout).

Returns

Simple rotation model settings object (derived from RotationModelSettings base class) with constant orientation of target in base frame.

Return type

SimpleRotationModelSettings

Classes

class RotationModelSettings

Base class for providing settings for automatic rotation model creation.

This class is a functional base class for settings of rotation models that require no information in addition to their type. Basic rotation model has constant orientation of the rotation axis (body-fixed z-axis) and constant rotation rate about this axis. Rotation models requiring additional information must be created using the factory functions which create the specific object derived from this base class.