Detemining Accuracy of Local Geoid Determined from Airborne Gravity Data

The methods for processing airborne gravimetry data are summarized.The effects of the downward continuation approaches and the filtering amount on the precise local airborne geoid determination are discussed in detail.The results show that the accuracy of airborne geoid with 3 cm can be obtained by all three downward continuation approaches,namely by the direct representation method,Tikhonov regularization and point-mass model,but the direct representation method may be optimal since it is not limited by the observed area and has little edge effect.It is also shown that the filtering amounts of 100-250 s can be all suited for airborne geoid determination,but a smaller amount e.g.100 s will be desired due to the less edge effect.The geoid determined from airborne gravity arrives 3 cm compared with the reference geoid on a 5′×5′ grid.