Impact of BRAGS’99 Airborne Gravimetric Data on Geoid Computations in Australia, and Possibilities for Utilisation of Bathymetric Information

Abstract

There are recognised deficiencies in the gravity data around the Australian coastline, which can best be repaired by the use of airborne gravimetry. The development of an Australian capacity in airborne gravimetry will not only allow improvements in local geoid modelling; but also will enable gravimetric measurements to be undertaken in the Antarctic region, contributing to local and global geoid modelling, and to the international scientific effort in the region.This paper describes the airborne gravimetric mission flown in the Barrier Reef region in October 1999. The mission was flown onboard the survey plane of the Laser Airborne Depth Sounder unit of the Royal Australian Navy during one of its routine bathymetric survey campaigns. The gravity data derived from this mission is used in local geoid determinations, and tested to determine what impact this new data has upon the precision of the derived geoid.The gravimetric and bathymetric data obtained during this mission are used to investigate the validity of models for predicting gravity anomalies from bathymetry. Extensive bathymetric charting exists for the Australian coastline, and if sufficient additional constraints are introduced, this data source may prove useful for predicting gravity anomalies in unsurveyed areas. This paper investigates the feasibility of such an approach.KeywordsAirborne gravimetrygeoid computationbathymetrygravity prediction