GEOID COMPUTATION BY ANALYTICAL AND DISCRETE SPECTRUM

Abstract

For the computation of geoid undulation applying gravity anomalies, FFT technique is used. The effects of the analytical and the discrete spectra of kernel functions and that of zero-padding in FFT are studied. The conclusion obtained from the practical computation is that the discrete spectrum seems to be better than the analytical one. Also, to eliminate the effect of circular convolution, 100 % zero-padding should be used. The computed geoidal undulations were compared with 45 GPS/Levelling stations. Results show that the differences between obtained geoidal undulations and GPS/Levelling have a standard deviation at 35 cm.