基于天文角度观测的机载惯性/天文组合滤波算法研究

Research of Airborne INS/CNS Integrated Filtering Algorithm Based on Celestial Angle Observation

针对采用天文/惯性位置组合时对导航选星有特殊要求,提出了基于天文角度观测信息的机载惯性/天文组合滤波方案及算法。对基于天文角度观测的INS/CNS组合导航系统的原理进行了充分阐述,分析并建立了基于单星或多星观测条件下的组合导航系统线性化量测方程,并针对角度观测时高度通道不可观的特点,增加了气压高度输出为系统的观测量,并在此基础上设计了组合滤波器算法。最后进行了组合导航系统仿真,并通过协方差分析的方法对比分析了单星和双星观测条件下的滤波性能。仿真结果表明,即使是在单星观测条件下,组合导航系统也能获得较好的定位精度;若观测星数增多,则可以大大提高系统性能,表明该组合导航系统设计方案是成功可行的。

Because of the special require of selecting navigational stars in CNS/INS position integrated navigation system, the scheme and algorithm of airborne INS/CNS integrated navigation based on celestial angle observation have been presented. The theory of INS/CNS integrated navigation system based on celestial angle observation information has been discussed adequately. The integrated navigation system linearization observation equation has been constructed, which can be suitable for one navigational star or more navigational stars. Because of the information of height can＇ t be got through the angle observation, so the air height output is be added to the system. Built the integrated filtering algorithm and perform the simulation. With the analysis of the cova- riance, the paper analyzed the filtering accuracy both one navigational star and two navigational stars. Simulation result shows that the position accuracy of the system can be improved highly even if there is only one navigational star. If there are more navigational stars, the system performance will be improved more. So the design of the integrated navigation system is successful.