基于伪距差分增强的分布式节点时间同步方法

摘要

传统时频同步方法维持分布式节点之间同步的精度较高,但并不适用于空间非接触节点的时频同步问题.本文提出一种基于伪距差分增强的时间同步方法,给出了系统原理和基本组成,运用总体最小二乘法解算分布式节点的先验钟差信息,并利用卡尔曼滤波构建了主从节点间的时间同步算法模型.仿真校验与结果分析显示,相比独立GPS授时同步,本文提出的系统同步算法能够提高空间分布式节点同步精度,在基线距离平均为25 km的条件下,可将节点同步精度控制在亚纳秒量级.%Traditional time synchronization method could reach a high precision for distributed nodes,but does not apply to the spatially non-contact nodes.In order to solve the above problems,a time synchronization method based on pseudorange differential GPS was proposed,and the system principle and synchronization scheme are given.Moreover,the clock model of the Anchor Nodes (ANs) is built to estimate synchronization parameter,which is solved by the Total Least Squares (TLS) method.The Kalman Filter (KF) method is derived from the theoretical time synchronization module,which can enhance the real timing and precision.The results of numerical simulating show that the proposed system synchronization and parameter estimation methods can control the synchronization accuracy of distributed node in sub-nanosecond level.