Yu Mingbiao, Cai Tijing
Instrument Science and Engineering College, Southeast University, Nanjing 210096, China.
Rev Sci Instrum. 2019 Jul;90(7):074501. doi: 10.1063/1.5093078.
Imperfections in the factors of a rotating accelerometer gravity gradiometer (RAGG), such as accelerometer mounting errors, circuit gain mismatch, accelerometer linear scale factor imbalances, and accelerometer second-order error coefficients, make the RAGG susceptible to its own motion. These motion errors easily cause saturation of the RAGG so that it is unable to work normally. In this study, we propose a scheme for continually adjusting the linear scale factors or mounting angles of the accelerometers to reduce motion sensitivity and for generating a compensation signal based on an analytical model of the RAGG, to compensate motion errors. A numerical model of the RAGG is used to simulate a real imperfect RAGG to allow an online error compensation experiment to be performed. In the experiment, the mean and standard deviation of the air turbulence are 100 mg and 20 mg (1 g = 9.81 m/s), respectively, and those of the angular velocity are 100 deg/h and 50 deg/h. It takes about 15 min for the RAGG online error compensation system to achieve convergence. In the converged state, the motion noise density of the RAGG is about 1 E/√Hz and scale factor balances of the order of 10 g/g are maintained. These experimental results suggest that the proposed online error compensation method is valid.
旋转加速度计重力梯度仪（RAGG）的各因素存在缺陷，如加速度计安装误差、电路增益失配、加速度计线性比例因子失衡以及加速度计二阶误差系数等，使得RAGG易受自身运动的影响。这些运动误差很容易导致RAGG饱和，从而无法正常工作。在本研究中，我们提出了一种方案，即持续调整加速度计的线性比例因子或安装角度以降低运动敏感度，并基于RAGG的解析模型生成补偿信号，以补偿运动误差。利用RAGG的数值模型来模拟实际存在缺陷的RAGG，从而进行在线误差补偿实验。在实验中，空气湍流的均值和标准差分别为100 mg和20 mg（1 g = 9.81 m/s²），角速度的均值和标准差分别为100 deg/h和50 deg/h。RAGG在线误差补偿系统大约需要15分钟才能达到收敛。在收敛状态下，RAGG的运动噪声密度约为1 E/√Hz，并且保持了10 g/g量级的比例因子平衡。这些实验结果表明所提出的在线误差补偿方法是有效的。
