GPS/SINS超紧组合导航系统可观测性分析

系统状态的可观测性决定了系统的滤波精度.目前,分析系统状态可观测性的主要方法是针对线性系统的,其中奇异值分解(SVD,Singular Value Decomposition)法可以对系统进行事前分析,并且计算简单,成为广泛使用的方法之一.然而集中滤波结构的全球定位系统/捷联惯性导航系统(GPS/SINS,Global Positioning System/Strapdown Inertial Navigation System)超紧组合模型的量测方程是非线性的,对非线性系统进行可观测性分析是非常困难的.针对这个问题,推导出了超紧组合模型线性的量测方程,并证明了该模型满足分段定常系统(PWCS,Piece-Wise Constant System)定理;使用奇异值分解法对其做可观测性仿真,并对实验结果做了全面分析.结果表明:系统状态的可观测性受载体运动状态影响,载体机动性越强,可观测的状态越多,可观测性越高.

Observability analysis of GPS/SINS ultra-tightly coupled system

The filter precision depends on the observability of system states. Various approaches were proposed to analyze the observability of the linear system states. Among those approaches, singular value decomposition (SVD) was commonly used to analyze the system beforehand owing to its computational simplicity. However, the measurement equation of global positioning system/strapdown inertial navigation systems (GPS/SINS) ultra-tightly coupled system based on the concentrated filter structure was nonlinear, which made it difficult to analysis the system observability. To solve this problem a linear measurement equation was derived. This GPS/SINS ultra-tightly coupled system model was proved to satisfy the piece-wise constant system (PWCS) theorem and the states' observability of the system were calculated based on the theory of SVD. The results show that the observability of states is affected by the maneuverability of carrier. The stronger maneuverability is, the more observable states are, the higher observability is.