ESTIMATION OF LOCAL PLANETARY GRAVITY FIELDS USING LINE OF SIGHT GRAVITY-DATA AND AN INTEGRAL OPERATOR

The gravity data coming from planetary probes are Doppler tracking observations which are sometimes reduced to Line-Of-Sight (LOS, the line joining the probe and the observer) gravity data. This direction-dependent representation is quantitatively difficult to use for geodetic and geophysical purposes. We present a new method of mapping LOS gravity data as gravity disturbances (gravity anomalies along a radial direction at a constant altitude). For this, we use an inversion procedure derived from Hotine's integral operator, with a Tikhonov-Arsenine regularization method. Different choices of the regularization parameter are presented in relation to data errors and method errors. After a study of a synthetic case, we apply the method to a real case, the region of Gula Mons (Venus), using Pioneer-Venus orbiter data. © 1992.