Noise Analysis and Suppression in a Calibration Measurement System for a Moving-Base Gravity Gradiometer

Rotating accelerometer gravity gradiometer (RAGG) is currently the only practical moving-base gravity gradiometer, which is carried by the vehicle along a specific survey path to measure the gravity field of the target region, playing an important role in resource exploration and auxiliary navigation. The dynamic performance of RAGG is the key to actual gravity gradient measurement. In order to analyse the dynamic performance of the self-developed RAGG, a calibration test was conducted by mounting the RAGG on a displacement platform with the speed of 1 mm/s. The measurement results exhibited significant drift and impulse noise, which seriously affect the measurement accuracy and limit the application of conventional methods. In order to suppress the measurement noise of RAGG, the Laplace distribution model of the measurement noise was established. Combined with the maximum likelihood estimation, the least absolute deviation estimation was proposed to fit and cancel the drift noise, and a specific weighted median filter was designed to eliminate the impulse noise. These methods successfully reduced the root mean square error of the RAGG calibration measurement from 76 E to 31 E, representing a 42% improvement compared to the conventional method, which effectively enhance the measurements accuracy of the self-developed RAGG.