Position measurements with the LaCoste and Romberg air/sea gravimeter

Abstract

The LaCoste and Romberg air/sea gravimeter with its three‐axis inertial platform may be operated in the same mode as the new inertial survey systems (ISS) to obtain relative positions, elevations, and gravity. In this mode of operation, the instrument is stopped at approximately 5‐minute intervals to obtain a zero‐velocity update to permit compensation for sensor drift and the effects of anomalous gravity. Two tests were made to determine the gravimeter’s ability to measure positions when used in this mode. The first test, carried out at Ottawa, Canada, indicated that although gravity errors as large as 6.0 mgal were observed due to the effects of platform damping and power source (motor‐generator) instability, elevations were obtained with a mean and standard error of 0.07 and 0.9 m, respectively, for two‐way traverses. No attempt was made to determine horizontal positions.