A REVIEW OF GRAVITY GRADIOMETER SURVEY SYSTEM DATA ANALYSES

The Gravity Gradiometer Survey System (GGSS) was designed to measure the local and regional gravity field from a ground or airborne moving platform. With the first and only airborne field test, the GGSS was able to recover five-arcminute by five-arcminute mean gravity anomalies to an accuracy of a few mGal. These results were obtained by flying the system, with an operational precision of about 10 Eotvos (ten-second average), on a grid of orthogonal tracks spaced 5 km apart at an altitude of about 700 m above the terrain. Despite perpetual navigation problems with the Global Positioning System and several periods of excessive system noise, the results of a performance analysis on 19 out of 128 tracks demonstrated the potential accuracy and efficiency of the GGSS as an airborne gravity mapping system. The ground tests (both road and railway), suffering from undue vehicle vibrations and from a lack of ground truth data, were correspondingly less successful, but they also showed no surprises in the system corrupted by these adverse conditions. Unfortunately, the GGSS program has terminated; and it is appropriate to reflect on its accomplishments. Without going into technical details, this somewhat historical review summarizes the field tests, the data reduction algorithms, and the test results, which together portray the breadth of expertise the program engendered in the area of gravity gradiometry.