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