关键词: 无线传感器网络, 绝对时钟同步, 能观测性, 线性变换

Abstract: Based on the observability analysis of the measurement model under the modern control theory,this paper proposes the observability problem of the absolute clock state measurement model. It is inspired by measured state vector space and state vector algorithm, and transformed into the isomorphic mapping principle of vector space essentially. It establishes the minimum mean square error (MMSE) observable decoupling measurement model under equivalent transformation with basic measurement unit (BMU). This method reveals the essence of symmetric measurement performance under two-way message exchange,and realizes Kalman filtering algorithm for clock state tracking under the necessary conditions that the measurement model satisfies the observability. The proposed algorithm does not depend on the optimized initial point setting, the initial point selection is robust,and it is also robust to changes in network connectivity. The simulation results show that the observable measurement model can achieve scale expansion, and the proposed algorithm has local and global uniform of MMSE measurement performance, which is close to the boundary of the Bayesian Cramer-Rao lower bound (CRLB) measurement performance.

Key words: wireless sensor network, absolute clock synchronization, observability, linear transformation