基于时域反射法土壤探头的性能研究  

Performance Study on the Soil Probe of Sensor Based on Time-domain Reflectometry

作　　者：石庆兰[1] 王一鸣[1] 王克栋[2] 冯磊[1] 

机构地区：[1]中国农业大学信息与电气工程学院,北京100083 [2]北京工商大学计算机与信息工程学院,北京100048

出　　处：《农机化研究》2011年第3期159-161,165,共4页Journal of Agricultural Mechanization Research

基　　金：国家"863"计划项目(2006AA10Z264)

摘　　要：TDR时域反射法(Time Domain Refletrometry)是近些年发展起来的一种测定土壤含水量的新技术,因其快速、简便、高可靠性、高精度等优点受到越来越多的关注。为此,介绍了基于相位检测的TDR时域反射法土壤探头的测试原理以及结构组成,从理论上推导出该土壤探针采用PVC绝缘涂层和增加探针首端与同轴电缆间的阻抗变换能够有效地增大测量值的线性范围,改善土壤水分含量与信号传播时间间的线性关系。从土壤针绝缘涂层的对比实验和阻抗变换影响的对比实验中验证了上述结论。With the increasing popularity of TDR（time domain refletrometry） techniques for measuring soil water content,it is critical to study the design of probes used for soil moisture measurement.This article introduces the measuring principle and the structure of a new kind of rod probe based on P-TDR.Compared with the metallic probe rods of conventional probes,the P-TDR rod probes need a PVC coating in order to increase the precision of measurements.A conclusion reached is that using the rod probes with a PVC coating can expand the linear range of measurement.By using impedance conversion between cable and probes,it can also improve the measured values.In order to verify the above mentioned conclusion,two experiments were carried out.One was rod probes insulation-coated experiment,the other was and experiment about the impact of impedance conversion on the measurement results.

关 键 词：土壤水分测量 时域反射法 土壤探头 相位检测 

分 类 号：S129[农业科学—农业基础科学]