Mathematic Model and Error Analysis of Moving-Base Rotating Accelerometer Gravity Gradiometer

Limited by manufacturing technology, in moving-base gravity gradiometry, accelerometer mounting errors and mismatch cause a rotating accelerometer gravity gradiometer (RAGG) to be susceptible to its own motion. In this study, we comprehensively consider accelerometer mounting errors, accelerometer linear scale factors imbalances, accelerometer second-order error coefficients, RAGG internal movement, and construct three RAGG models—namely, a numerical model, an 54 parameters analytical model, and a 25 parameters simplified analytical model. Moreover, by setting the gravitational gradient excitation of RAGG to zero, the RAGG motion error model is derived. The analytical model and motion error model are used to interpret the error propagation mechanism and develop RAGG technical solutions, such as motion error compensation, fault diagnosis, etc. The numerical model is used to facilitate the verification of the RAGG analytical model and RAGG technical solutions. We performed multifrequency gravitational gradient simulation experiment and dynamic sweep frequency experiments to verify the three RAGG models, and evaluate the dynamic noise floor of the analytical models. In dynamic experiments, standard deviation of RAGG vertical specific force grows from 10 to 40 mg (1 g = 9.8 m/s2); that of the lateral specific force grows from 5 to 20 mg; the noise density of the analytical model remains stable within 2.5 E/✓ Hz, and that of the simplified analytical model is in the range of 2.64–41.27 E/✓Hz.