Knowledge Bank

The undulations of the geoid may be computed from spherical harmonic potential coefficients of the earth's gravitational field. This report examines three procedures that refelct various points of view on how this computation should be carried out. One method requires only the flattening of a reference ellipsoid to be defined while the other two methods require a complete definition of the parameters of the ellipsoid. It was found that the various methods gave essentially the same undulations, provided that correct parameters were chosen for the reference ellipsoid. A discussion is given on how these parameters are chosen and numerical results are reported using recent potential coefficient determinations.