Abstract: For Wireless Sensor Network (WSN), many applications rely on the coordination of synchronized clock nodes. However, the crystal oscillator of the node is affected by itself and the external environment, so that the clock skew and clock offset change and then lead to the clocks falling out of synchronization. Consequently, a new clock synchronization algorithm based on distributed Kalman filter and consistency compensation, namely DKFCC, was proposed. First of all, the optimal estimation of the clock skew and offset was obtained by two-way message exchange mechanism and distributed Kalman filter. Then consistency compensation method based on the optimal estimation value of clock parameters was adopted to achieve clock synchronization. The experimental results show that compared with the Asynchronous Consensus-based time synchronization (AC) algorithm in the WSN with 100 randomly-deployed nodes, the Synchronous Root Mean Square Error (SRAMSE) of the DKFCC synchronization algorithm with virtual global consistency is reduced by about 95%, which means DKFCC synchronization algorithm has higher synchronization accuracy. At the same time, the proposed algorithm achieves synchronization from the clock parameter level without operating clock synchronization frequently, thus it has better energy efficiency compared to AC synchronization algorithm.

Key words: Wireless Sensor Network (WSN), clock synchronization, Kalman filter, state estimation, consistency compensation

摘要： 针对无线传感器网络（WSN）的众多应用都需要依赖时钟同步的节点协同完成，而由于节点的晶体震荡器受自身以及外界环境的影响，使得节点时钟偏斜和时钟偏移两个参数发生变化导致时钟不同步问题，提出了基于分布式卡尔曼滤波估计的一致性补偿时钟同步算法DKFCC。该算法首先利用双向信息交换机制以及分布式卡尔曼滤波实现时钟偏斜和偏移两个参数的最优估计，然后基于时钟参数的最优估计值采用一致性补偿方法实现节点的时钟同步。实验结果表明：在100个节点随机部署的WSN中，采用虚拟全局一致性方式的DKFCC同步算法比异步一致性同步（AC）算法的同步均方根误差（SRAMSE）值降低了约95%，具有较高的同步精度；同时，所提出算法从时钟参数层面实现同步，无需频繁地进行时钟同步操作，相比AC算法更节能。

关键词: 无线传感器网络, 时钟同步, 卡尔曼滤波, 状态估计, 一致性补偿