No abstract

No abstract

No abstract

No abstract

In this paper, a modified chi-square test is proposed to develop an autonomous fault detection and identification system for the navigation system in the lunar lander. The conventional fault detection logics, which is based on state chi-square test have had a limitation on fault identification. The proposed modified chi-square test computes modified chi-square parameter (MCP) by comparing the estimated states which is estimate on local filters to the propagated states. Because the MCP only contains the information of the respective sensor measurement, the MCP from failed measurement is contaminated by the fault. Thus, the MCP from other measurements is not contaminated by the fault, then the MCP from failed sensor can be easily distinguished by finding a diverging MCP signal. Using the proposed method, the fault of the lunar lander can be efficiently detected and isolated.