Error sources in airborne gravimetry employing a spring-type gravimeter.

Experiences from recent airborne gravity campaigns undertaken by National Survey and Cadastre - Denmark (KMS) in cooperation with different partners are described in this paper. Data from surveys over Great Barrier Reef Australia, in the Baltic Sea and in Greenland are analyzed with emphasis on system performance, data validation and especially error sources. All campaigns employed a LaCoste and Romberg air/sea gravimeter. Both internal crossover analysis and comparison to existing surface data indicate a noise level around 1.5 to 2 mGal at 6 km resolution. Examples from a sedimentary basin in the northeast Greenland shelf region show that the resolution and accuracy of the system are sufficient for mapping of geological structures of interest to hydrocarbon exploration. Salt structures were recognized in an earlier marine seismic survey and the related negative gravity anomalies are clearly mapped by the airborne gravity system. Due to its good drift characteristics the LaCoste and Romberg gravimeter has proven to be a reliable and operational tool for geodetic purposes, e.g. provide bias free data for local geoid models. Consequently data from adjacent tracks can be mixed directly in the filtering stage of the processing. Processing algorithms that ensure an unbiased recovery of the longest wavelength components are described in some detail.