航空重力与重力梯度测量对惯性稳定平台的需求分析

从航空重力与重力梯度测量原理出发,先后导出航空重力与重力梯度测量的观测方程和测量误差方程,然后依据地球重力场特征和功率谱的相关理论,结合航空重力与重力梯度测量中的GPS定位、惯性稳定平台的指向和稳定性、加速度计和梯度仪的误差模型,分析了航空重力与重力梯度测量对稳定平台的需求,在此基础上以航空重力测量中国外常用的双水獭(Twin-Otter)固定翼飞机的实际飞行参数为例,通过数值计算给出了航空重力测量分辨率达到1 mGal时,对惯性稳定平台的角度指向精度、稳定性和随机漂移的要求分别为0.0005°、0.006°/h/Hz和0.0003°/h;航空重力梯度测量分辨率1 E时,对稳定平台对应的指标要求分别降低为0.5°、0.01°/hr/Hz和0.01°/hr。

Requirement analysis of moving-base platform in airbrone gravimetry and gravity gradiometry

Based on the principle of moving-base gravimetry system,we deduce the mathematical models of measurement and error equations for airbrone gravimetry and gravity gradiometry.According to the inherent characteristic of the Earth gravity field and the basic theories of power spectral density,we analyze the specific requirements of the inertial stabilized platform in airbrone gravimetry and gravity gradiometry with known sensor error models for GPS receiver,stabilized platform,accelerometer,and gradiometer.By using the experiential models of acceleration and angular rate fitting from the practical flights of a Twin-Otter aircraft,we present the requirements for the stabilized platform by the numerical computation,that is,for the airbrone gravimetry with a resolution of 1 mGal,the requirements for the orientation error,stability and random noise of angular rate of the stabilized platform are 0.0005°,0.006°/h/ and 0.0003°/h,respectively,and for the airbrone gravity gradiometry with a goal of 1 E,the corresponding requirements for the stabilized platform are lowered to 0.5°,0.01°/h/(Hz)～(1/2),and 0.01°/h,respectively.