Conversion from geocentric to ECEF coordinates including a LOS
pos (Vector3) – Geodetic position (h,lat,lon)
los (Vector2) – Geodetic line-of-sight (za,aa)
ecef (~pyarts3.arts.Vector3) – Position (x,y,z)
decef (~pyarts3.arts.Vector3) – Normalised direction vector (dx,dy,dz)