长距离大面积农田土壤测温系统的研究

发布时间：2018-05-18 00:31

  本文选题：农田测温 + 光纤传感　； 参考：《吉林农业大学》2015年硕士论文

【摘要】：针对农业发展趋势及农业耕作技术的发展现状和实际问题,本文研究了温度对农业生产的影响尤其是耕作层土壤温度对农业的直接影响。本文进行了新兴的光纤传感技术在农业上应用的可能性的研究,并对农业免耕技术等保护性耕作方式存在的问题进行分析,基于光纤传感理论分析进行系统选型研究,根据不同光纤测温原理的不同,可以集成多种光纤传感测温系统。并主要分析并比较这几种系统的特点并选择最适合大面积农田应用的分布式光纤温度传感系统,对光纤传感系统测温原理进行深入的研究,分析了光波在光纤中传输的散射现象,找到包含温度信息的散射光,对拉曼散射中的斯托克斯光和反斯托克斯光的物理关系进行研究,对土壤温度传感系统温度定标之后,只要测量出Anti-Stokes和Stokes光强度,就能确定分布式光纤温度传感系统中光纤各个点的温度值,从而确定温度场的分布情况。通过各种种类测温原理特点的研究,确定最适合大面积农田测温系统的最佳光纤传感温度解调,测量类型。对光时域反射技术进行研究,从而保证系统中反映的光纤中各点温度信息与位置信息相互对应。对耕作层土壤温度的长距离/大面积实时监测进行了研究分析以及实验。本文对系统设计中关键技术问题进行了说明,并对具体实施的硬件搭建,系统定位技术,温度解调技术,波分复用技术进行了深入的研究,并对相应的系统硬件进行了调研,采购,测试与系统集成。本文也详细介绍了相关硬件的技术指标,同时对测温系统操作软件的开发思路及软件应用方法进行了解析。通过对面积农田测温系统定标方法进行研究,总结出具体的实验定标方法和A,B,K常数定标公式及实验方法。通过实验得出应用于大面积农田的新定标方法。除了实现对大面积农田土壤的温度分布情况实时的检测,并定期储存数据的基本功能外,还要实现定温报警和故障报警两个主要功能。定温报警功能是结合农作物的三基点温度为基础的分级报警并指明温度对应的地理位置。故障报警功能是根据铺设在大面积农田上的传感光缆长度范围内采集到的电压值得强弱判断是否出现光缆断裂或破损。最后对系统进行了长期的试运行实验,并针对长期运行过程中遇到的温漂问题做了详细的实验与研究。成功解决温漂问题之后,对系统的温度分辨率、空间分辨率、测量长度、测量精度、系统响应时间等做了全面优化,系统实最终最大测量距离10公里,空间分辨达到1m,温度精度达到1℃,系统响应时间小于4s。
[Abstract]:In view of the development trend of agriculture and the present situation and practical problems of agricultural tillage technology, this paper studies the effect of temperature on agricultural production, especially the direct influence of soil temperature on agriculture. In this paper, the possibility of the application of new optical fiber sensing technology in agriculture is studied, and the problems of conservation tillage such as no-tillage technology are analyzed, and the system selection based on the theoretical analysis of optical fiber sensing is studied. According to the different optical fiber temperature measuring principle, many kinds of optical fiber sensing temperature measuring system can be integrated. The characteristics of these systems are analyzed and compared, and the distributed optical fiber temperature sensing system, which is the most suitable for the application of large area farmland, is selected, and the principle of temperature measurement of the optical fiber sensing system is deeply studied. The scattering phenomenon of light wave in optical fiber is analyzed, the scattering light containing temperature information is found, the physical relationship between Stokes light and anti-Stokes light in Raman scattering is studied, and the temperature calibration of soil temperature sensing system is carried out. Once the light intensity of Anti-Stokes and Stokes is measured, the temperature values of each point in the distributed optical fiber temperature sensing system can be determined, and the distribution of the temperature field can be determined. Through the study of the principle and characteristics of various kinds of temperature measurement, the optimum temperature demodulation and measurement type of optical fiber sensor which is most suitable for large area farmland temperature measurement system is determined. The optical time domain reflection (OTDR) technique is studied to ensure that the temperature information and the position information of the optical fiber reflected in the system correspond to each other. The long distance / large area real time monitoring of soil temperature in tilling layer was studied and analyzed. In this paper, the key technical problems in the system design are explained, and the system hardware construction, system positioning technology, temperature demodulation technology, wavelength division multiplexing technology are deeply studied, and the corresponding system hardware is investigated. Procurement, testing and system integration. This paper also introduces the technical specifications of the related hardware in detail, and analyzes the development idea and the application method of the operating software of the temperature measuring system at the same time. Based on the study of the calibration method of the area temperature measurement system, the specific experimental calibration method, the formula and the experimental method for the calibration of the BK constant of the area are summarized. A new calibration method applied to large area farmland was obtained through experiments. Besides the basic function of detecting the temperature distribution of large area farmland in real time and storing the data periodically, the two main functions of fixed temperature alarm and fault alarm are also realized. The function of constant temperature alarm is based on the three basis point temperature of crops and indicates the geographical position of the corresponding temperature. The function of fault alarm is to judge whether the cable is broken or broken according to the voltage collected in the length range of the sensor cable laid on a large area of farmland. Finally, the system is tested for a long time, and the temperature drift problem encountered in the long run is studied in detail. After successfully solving the temperature drift problem, the system's temperature resolution, spatial resolution, measurement length, measurement precision, system response time and so on are optimized. The spatial resolution is 1 m, the temperature precision is 1 鈩，

本文编号：1903581