nvector._core.E_rotation¶
-
E_rotation
(axes='e')[source][source]¶ Return rotation matrix R_Ee defining the axes of the coordinate frame E.
Parameters: - axes : ‘e’ or ‘E’
defines orientation of the axes of the coordinate frame E. Options are: ‘e’: z-axis points to the North Pole along the Earth’s rotation axis,
x-axis points towards the point where latitude = longitude = 0. This choice is very common in many fields.
- ‘E’: x-axis points to the North Pole along the Earth’s rotation axis,
y-axis points towards longitude +90deg (east) and latitude = 0. (the yz-plane coincides with the equatorial plane). This choice of axis ensures that at zero latitude and longitude, frame N (North-East-Down) has the same orientation as frame E. If roll/pitch/yaw are zero, also frame B (forward-starboard-down) has this orientation. In this manner, the axes of frame E is chosen to correspond with the axes of frame N and B. The functions in this library originally used this option.
Returns: - R_Ee : 3 x 3 array
rotation matrix defining the axes of the coordinate frame E as described in Table 2 in Gade (2010)
- R_Ee controls the axes of the coordinate frame E (Earth-Centred,
- Earth-Fixed, ECEF) used by the other functions in this library
Examples
>>> import numpy as np >>> import nvector as nv >>> np.allclose(nv.E_rotation(axes='e'), [[ 0, 0, 1], ... [ 0, 1, 0], ... [-1, 0, 0]]) True >>> np.allclose(nv.E_rotation(axes='E'), [[ 1., 0., 0.], ... [ 0., 1., 0.], ... [ 0., 0., 1.]]) True