全张量重力梯度数据误差分析及补偿

Error Analysis and Compensation of Full Tensor Gravity Gradiometer Measurements

针对用于航空移动平台的高精度全张量重力梯度测量系统,深入研究了梯度仪12个加速度计按3个不同旋转轴圆盘形成差分组合的结构。在确认该结构具有有效抑制运动共模加速度、减少外界环境干扰、实现高精度探测优点的同时,着重分析了重力梯度仪测量误差的来源和影响。研究表明,主要影响包括仪器固有随机噪声和外界确定性噪声。为定量描述影响程度,推导了在航空动态环境下的测量方程,并分离出加速度计的性能不匹配、平台不稳定、圆盘转速不稳定3个主要固有因素,从时间域和频率域角度定量分析固有影响因素的噪声水平。试验分析表明,通过利用Simulink仿真系统可以获得固有因素产生的噪声水平,并提出抑制方案。针对搭载环境测量误差,还分析了实测飞行中姿态和质量的改变对重力梯度测量值造成的环境影响,提出了基于点质量源的自身梯度校正方法。

For the high precision full tensor gravity gradiometry （FTG ）used in airborne moving platform,the authors study the difference composite structure of gradiometry,which have 1 2 accelerometers installed on three different rotation disc.Upon confirmation of the structure which can restrain the common mode acceleration,reduce the interference of extent environment and have the advantage of high precision detection,the authors analyze the error sources and influences in gradiometer measurements.Research shows that main effects include instrument inherent random noise and external deterministic noise. In order to describe the influence quantificationally,the authors derived the measuring equation of FTG in the dynamic environment,and analyzed the noise level of intrinsic factors in time domain and frequency domain, identified three main intrinsic factors：Accelerometer ’ sperformance mismatching;Platform instability and unstable disc rotating speed.Experiments using Simulink system can obtain the noise level of intrinsic factors and put forward the inhibition scheme. Aiming at the external deterministic noise,we also analyzed the influence of changing of attitude and quality in flight to measured gradients and put forward a method to correct the self-gradient based on a point mass.