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