The classical astro-geodetic leveling is a reasonably accurate method to derive the terrestrial geoid, provided a starting point is given. It combines the precise determination of the true zenith (geographic or astronomical positioning) with geodetic measurements and coordinate calculations.
Astro-geodetic geoid solutions are computed by the spatial integration of the two components of vertical deflections.
Modern astro geodetic methods use also satellite measurements (optical and electronical, LASER etc.), with CCD observations, and combinations of terrestrial and GPS data (espec. for precise heighting and for the stabilisation of geoid solutions).