重力扰动对SINS水平姿态的影响

为研究动基座下捷联惯导系统(Strapdown Inertial Navigation System, SINS)水平姿态误差角与水平重力扰动间的关系,推导了南北方向、东西方向匀速直线运动时,SINS纯惯性解算的水平姿态误差与水平重力扰动间的传递函数,并分析了传递函数的零极点分布;推导了组合导航模式下,水平姿态误差角与水平重力扰动间的传递函数;通过仿真分析了纯惯性解算和组合导航模式下传递函数的幅频特性。组合导航相对于纯惯性解算模式,截止频率更大,SINS姿态误差角受更多高频重力扰动信号的影响,因此,组合导航模式需要更高分辨率的重力扰动数据来进行重力扰动补偿。此外,在对高精度SINS进行重力扰动补偿时,对于重力扰动分辨率的需求是有限度的,过于精细的重力扰动数据只会带来测量和存储压力,不能提高SINS的姿态精度。

Influence of gravity disturbance for SINS horizontal attitude

In order to study the relationship between horizontal attitude error angle and horizontal gravity disturbance of SINS (strapdown inertial navigation system) on moving base, the transfer function between horizontal attitude error and horizontal gravity disturbance on SINS mechanization was deduced in uniform linear motion in North-South direction and East-West direction. The distribution of zero and pole of transfer function was analyzed. In addition, the transfer function between horizontal attitude error angle and horizontal gravity disturbance was analyzed in integrated navigation mode. The amplitude-frequency characteristics of transfer function on SINS mechanization and integrated navigation mode were analyzed by simulation. Compared with the SINS mechanization, the cut-off frequency of integrated navigation mode was higher, and the attitude error angle of inertial navigation was affected by high-frequency gravity disturbance signals more obviously. Therefore, the INS needs higher resolution gravity disturbance data to compensate the gravity disturbance in the integrated navigation mode. However, there is a limit for the resolution of gravity disturbance used to compensate for the high-precision inertial navigation system. Too fine gravity disturbance data will only bring cost for measurement and storage instead of improving the attitude accuracy of the inertial navigation system.