捷联惯导系统的误差模型与仿真

Error model and simulation of strapdown inertial navigation system

为研究捷联惯导系统短时间导航精度,建立了导航误差数学模型,分析了惯性器件误差对系统导航精度的影响。应用捷联惯性导航原理,针对系统短时间导航的特点,简化了载体在导航坐标系的导航方程;由惯性器件安装误差与陀螺仪等效零漂经过方向余弦矩阵变换建立载体姿态误差方程;结合导航方程、姿态误差方程与惯性器件误差推导出载体速度误差与位置误差数学模型。在此基础上,建立了误差状态空间方程与误差模型框图。在Matlab/Simulink环境下建立了误差数学模型计算模块,用捷联惯导算法与误差模型共同解算地面150s导航试验数据。结果表明:导航系X轴的相对系统误差<20%,Y轴、Z轴的相对系统误差<4%,验证了误差数学模型的正确性。此外,分析了加速度计精度的变化对短时间工作的捷联惯导系统导航误差产生的基本影响。

In order to achieve the accuracy of short-time navigation of a Strapdown Inertial Navigation System （SINS）,a navigation error mathematic model is established, and the effect of inertial device errors on the navigation accuracy of the system is analyzed. Aiming at the characteristic of short-time navigation,the navigation equation of carrier in a navigation coordinate is simplified with strapdown inertial navigation mechanism,then the attitude error equation of carrier is deduced by installation errors of inertial devices and the equivalent zero-shift of the gyroscope. Combing with the navigation equation,attitude error equation and the errors of inertial devices,the mathematic models of velocity errors and position errors are derived. Based on the error mathematic models, the state-space model and the block diagram of error models are established. Finally,a module of error models is built in Matlab/Simulink and is combined with the strapdown inertial navigation algorithm to calculate navigation data in ground within 150 s. The experimental results show that the relative system error of x-axis of navigation coordinate is less than 20%, and those of y-axis and z-axis are less than 4%, respectively. Furthermore, the influences of change of an accelerometer accuracy on SINS navigation errors are analyzed.