Functions for handling geographical coordinate systems and reference ellipsoids. If nothing else is stated: Latitudes range [-90,90] and longitudes [-180,180]. Cartesian coordinates follow the Earth-centred earth-fixed (ECEF) system. That is, the X axis passes (lat,lon)=(0,0), Y axis (0,90) and Z axis (90,x). Reference ellipsoids are specified by the equatorial radius (r) and its eccentricity (e), as a vector of length two: ellipsoid = [r,e] (this fits the definition used in Matlab's mapping toolbox) The local Line of sight angles are defined following the EAST-NORTH-UP system: za aa 90 0 points towards north 90 90 points towards east 0 aa points up