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 is the projection of rcoord - r along velocity, tangent to the track. W is the projection along V cross r, normal to the orbital plane. N is the in-plane projection 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)