改进故障隔离的容错联邦滤波

为了解决重置模式下联邦滤波器中子系统故障对导航系统污染的问题,提出利用故障检测函数构建时变量测噪声的容错联邦滤波结构。通过将故障子滤波器等价为量测噪声趋于无穷大的正常系统,来取代传统的故障隔离方法;推导出了子滤波器对应的最优估计值,用以消除子滤波器估计次优性对故障检测的影响;采用动态信息分配系数,以减少故障信息对全局估计的影响。采用惯性/天文/景象/地形(INS/CNS/SMNS/TERCOM)的组合导航系统进行了仿真验证,结果表明该容错联邦滤波方法在子系统发生故障时的估计性能优于故障隔离方法。因此,所提方法具有提高故障子滤波器精度、保证无故障子滤波器鲁棒性以及全局估计精度的优势,具有较高的实用价值。

An improved fault tolerant federated filter with fault isolation

In order to deal with the problem that the fault in any subsystem would affect navigation system in the reset mode federated filter, a fault tolerant federated filter using fault detection function to construct time-varying measurement noise is proposed. In this new structure, the faulty sub-filter is equivalent to a normal system whose measurement noise tends to infinity to replace the traditional fault isolation method. The optimal estimation values of the corresponding sub-filters are derived to eliminate the influence of suboptimality of the sub-filters'' estimation to fault detection. A dynamic information distribution algorithm is presented to reduce proportion of fault sub-filters'' estimation information. The simulation based on inertial navigation system/celestial navigation system/scene matching navigation system/terrain contour matching (INS/CNS/SMNS/TERCOM) integrated navigation system is carried out. Simulation results show that the estimation performance of the proposed method is better than the fault isolation method. Therefore, the proposed method has the advantages of improving faulty sub-filters'' accuracy, ensuring healthy sub-filters'' robustness, and making the performance of global estimation smooth. It has highly practical value.