计算机串口记时延迟的测量与分析  

Measurement and analysis of the timing delay for serial port in PC

作　　者：何峰 郑勇[2] 骆亚波[2] 郭睿 

机构地区：[1]61081部队,北京100094 [2]信息工程大学测绘学院,郑州450052

出　　处：《测绘科学》2009年第3期41-43,共3页Science of Surveying and Mapping

摘　　要：动态测量中,需要记录观测量的观测时刻,时刻作为测量的基本观测量,需要较高的计时精度,通过串口利用计算机计时是一种便捷可行的方法,但串口的时延是必须要考虑的因素。本文介绍了计算机串口计时的原理及影响其时延的相关因素,阐述了进行时延测量的方法,并通过实验对影响串口时延的5种因素进行了相应的测试和分析,实验结果表明,通常情况下串口时延在毫秒级,通过提高计时程序优先级的方法可成功将时延减小至0.35m s以内;低动态条件下串口时延对动态测量的影响较小,在某些检测设备中甚至可以忽略。It is essential to record the time information in dynamic surveying, which requires high precision as one of the basic observation. It is a convenient and feasible method to record the time by the serial port in PC, but the time delay should be taken into account. This paper introduces the principle of PC timing by serial port and the correlative factors which influence time delay. The inspecting method for time delay is illustrated, and then the experiments are carried out in which the influences of different correlative factors on time delay are tested and analyzed. According to the experiments, the time delay is equal to some milliseconds, which could be reduced to 0. 35ms through the method of enhancing the process priority of the timing program; the influence of time delay is not evident to dynamic surveying on the condition of low velocity, and it may even be ignored in some inspecting equipments.

关 键 词：串口 时延 动态测量 进程优先级 

分 类 号：TN791[电子电信—电路与系统]