Factors affecting FFT gravimetric geoid determination precision

The Fast Fourier Transformation (FFT) has become a routine mathematical too l for the refinement of the Earth's gravity field, such as the computation of precise gravimetric geoid and terrain corrections, particularly over a l arge area. This paper presents ideas and methodologies to evaluate the accu racy of geoid undulation computations using FFT. A global geopotential mode l is used as a 'ground truth' gravity field model to assess the geoid deter mination precision by using FFT technique. It is demonstrated that special considerations must be given for a high precision FFT gravimetric geoid det ermination. A maximum of a few decimetres error could be introduced by the FFT algorithm if the gravity anomalies are not long wavelength filtered and /or no zero padding is applied. (C) 2000 Elsevier Science Ltd. All rights r eserved.