dynamic_two_vector_frame

giant.rotations.frames:

giant.rotations.frames.dynamic_two_vector_frame(primary_vector_func, secondary_vector_func, primary_axis, secondary_axis, return_rotation=False)[source]

Create a dynamic (time dependent) 2-vector frame function.

This is particularly useful in conjunction with the spice interface functionality.

For instance, we can define a time dependent earth nadir frame using the following:

>>> from giant.utilities.spice_interface import SpicePosition
>>> from giant.rotations import dynamic_two_vector_frame
>>> from datetime import datetime
>>> z_dir_fun = SpicePosition('EARTH', 'J2000', 'NONE', 'MY_SPACECRAFT')
>>> x_const_fun = SpicePosition('SUN', 'J2000', 'NONE', 'MY_SPACECRAFT')
>>> nadir_frame_fun = dynamic_two_vector_frame(z_dir_fun, x_const_fun, 'z', 'x', return_rotation=True)
>>> current_rotation_inertial_to_nadir = nadir_frame_fun(datetime.now())
Parameters:

  • primary_vector_func (Callable[[datetime | Timestamp], ndarray]) – Function that returns the primary vector for a given datetime

  • secondary_vector_func (Callable[[datetime | Timestamp], ndarray]) – Function that returns the constraint for the secondary vector for a given datetime

  • primary_axis (Literal['x', 'y', 'z']) – The axis corresponding to the primary vector

  • secondary_axis (Literal['x', 'y', 'z']) – The axis corresponding to the secondary vector

  • return_reotation – whether to return as a .Rotation object (True) or as a numpy array containing the rotation matrix

  • return_rotation (bool)

Returns:

callable that returns the rotation matrix for a given datetime

Return type:

Callable[[datetime | Timestamp], ndarray | Rotation]