APPLICATION OF A SPHERICAL FFT APPROACH IN AIRBORNE GRAVIMETRY

The basic idea of this paper is to modify Poisson's integral for harmo nic downward continuation into a convolution formula in the space doma in. In this manner, the Past Fourier Transform can be applied. The met hod is applied to airborne gravimetry, motivated especially by the Gre enland survey. The accuracy of data continuation from the flight-level to the ground is analysed. In particular, the influence of latitudina l extension is investigated, since the introduced convolution formula is exact only for the mid-parallel of the analysed area. The results o btained justify the conclusion that the introduced method is applicabl e to processing of real data. Extended quadratic areas (up to 2500 km x 2500 km) in equatorial areas and up to 500 tm x 500 km in regions wi th latitudes about 75 degrees) can effectively be processed in one sin gle procedure.