rv_to_ntw

ssapy.utils.rv_to_ntw(r, v, rcoord)[source][source]

Convert coordinates to NTW coordinates, using r, v to define NTW system.

T gives the projection of (rcoord - r) along V (tangent to track) W gives the projection of (rcoord - r) along (V cross r) (normal to plane) N gives the projection of (rcoord - r) along (V cross (V cross r))

(in plane, perpendicular to T)

Parameters:

r (array_like (n, 3)) – central positions defining coordinate system
v (array_like (n, 3)) – velocity defining coordinate system
rcoord (array_like (n, 3)) – positions to transform to NTW coordinates

Returns:

ntw – n, t, w positions

Return type:

array_like (n, 3)