矿山物联网中的时间同步影响因素研究与实测

Impaction Factors of Time Synchronization and Experimental Analysis in Internet of Mine Things

精确的时间同步是准确反应感知信息的时序特征和内部规律的关键。提出了矿山物联网精确时间同步的网络模型,引入PTP协议作为时间同步的核心算法;探讨了矿山物联网环境同步精度的影响因素,包括网络延时、节点时钟漂移、节点故障和上下行流量不对称等,并根据影响因素的成因给出了可行的解决办法。实测数据表明,同步精度尽管受多种因素的影响,但是能够满足多数矿山物联网应用的需求,且主、从时钟之间的时间偏移具有明显的正态分布特征。进一步提高同步精度有赖于硬件的配合,实现数据链路层或物理层层面的同步。

Precise time synchronization is the safeguard of sequential characteristics and interior rules of perception information. After the introduction of network model of time synchronization, the modified PTP is employed as the core algorithm for time schedule. The key influential factors are analyzed, such as the network delay, time drift, node fault, asymmetry between upstream and downstream data, and then solutions are put forwarded according to their causes of formation. The experiments show that the time offset between primary and slave clocks follows normal distribution, and the synchronization precision meets needs of most mine applications. To further enhance this precision, we need to make time synchronization at data link layer or physical layer.