基于光纤干涉法的高精度水位检测系统软件解调的研究
发布时间：2018-11-24 14:58
【摘要】：海啸灾害破坏性极强,对海啸的预警技术的研究非常紧迫。水位检测是预警海啸一个重要手段,传统的水位检测技术不能满足海洋水位的监测需求,因此需研究新的测量方法使得监测结果更加实时准确,从而达到防灾减灾的目的。光纤传感技术应用于水位的检测已经成为一种趋势,光纤水位传感器是一种新型的水位测量技术,它具有抗电磁干扰、抗化学腐蚀、精度高等优点,并可应用在十分复杂的海洋环境中,具有很高的科研价值和实用性。首先,在深入研究光纤干涉水位传感器的结构设计和工作原理的基础上,从理论角度出发,介绍了光波的干涉原理以及光纤应力应变过程中光波相位的调制原理;推导了水位与光波的相位变化之间的函数关系;分析了3*3耦合器耦合特性,得出输出的光存在2?3的相位差的结论,并依此特性建立了可判向的马赫-曾德尔(Mach-Zehnder)干涉型光纤水位检测系统。然后,鉴于信号解调模块是系统的重要部分,本文在完成了实验基础硬件制备的基础上,提出了采用动态双阈值条纹计数检测法应用于系统的信号解调,在提高系统的分辨率的同时也降低了对传感探头动态范围的要求;系统利用虚拟仪器将计算机和硬件模块结合起来,实现了相位信号解调和水位信息的实时显示。与传统的电路计数方法相比,软件解调方法可降低制作成本,缩短系统制作周期;也可避免硬件电路引入的电噪声,使信号处理变得更加灵活。最后,进行了光纤水位检测系统软件解调方案的实验验证,实验结果和信号分析表明,该水位传感系统的线性相关系数达到0.99991;经过计算模拟,得到系统最高分辨率为1.59 mm,测量精度为满量程的0.01%,达到了预期的精度指标。由此证明,基于光纤干涉法的高精度水位检测系统软件解调方案是可行的,其广阔的应用前景非常值得我们深入的研究。
[Abstract]:Tsunami disaster is extremely destructive, and the research of tsunami warning technology is very urgent. Water level detection is an important means of tsunami warning. Traditional water level detection technology can not meet the needs of ocean water level monitoring, so it is necessary to study new measuring methods to make the monitoring results more real-time and accurate, so as to achieve the purpose of disaster prevention and mitigation. The application of optical fiber sensing technology in water level detection has become a trend. Fiber optic water level sensor is a new type of water level measurement technology, which has the advantages of anti-electromagnetic interference, anti-chemical corrosion, high precision and so on. It can be used in very complex marine environment and has high scientific research value and practicability. Firstly, on the basis of deeply studying the structure design and working principle of optical fiber interferometric water level sensor, the interference principle of optical wave and the modulation principle of optical wave phase in the process of stress and strain of optical fiber are introduced from the theoretical point of view. The functional relationship between the water level and the phase change of light wave is derived. Based on the analysis of the coupling characteristics of the 3 ~ (3) coupler, the conclusion that the output light has a phase difference of 2 ~ (3) is obtained. According to this characteristic, a discriminable Mach-Zehnder interferometric optical fiber water level detection system is established. Then, in view of the signal demodulation module is an important part of the system, based on the completion of the experimental hardware preparation, a dynamic dual-threshold fringe count detection method is proposed for the signal demodulation of the system. At the same time, the resolution of the system is improved and the dynamic range of the sensor is reduced. The system combines the computer and hardware module with virtual instrument to realize the demodulation of phase signal and the real-time display of water level information. Compared with the traditional circuit counting method, the software demodulation method can reduce the production cost and shorten the production cycle of the system. It can also avoid the electrical noise from the hardware circuit and make the signal processing more flexible. Finally, the experimental results and signal analysis show that the linear correlation coefficient of the water level sensing system is 0.9991. Through the calculation and simulation, the system with the highest resolution of 1. 59 mm, is obtained, and the precision of the system is 0. 01, which reaches the expected precision index. It is proved that the software demodulation scheme of high precision water level detection system based on fiber-optic interferometry is feasible, and its broad application prospect is worthy of further study.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.25;P714.1
[Abstract]:Tsunami disaster is extremely destructive, and the research of tsunami warning technology is very urgent. Water level detection is an important means of tsunami warning. Traditional water level detection technology can not meet the needs of ocean water level monitoring, so it is necessary to study new measuring methods to make the monitoring results more real-time and accurate, so as to achieve the purpose of disaster prevention and mitigation. The application of optical fiber sensing technology in water level detection has become a trend. Fiber optic water level sensor is a new type of water level measurement technology, which has the advantages of anti-electromagnetic interference, anti-chemical corrosion, high precision and so on. It can be used in very complex marine environment and has high scientific research value and practicability. Firstly, on the basis of deeply studying the structure design and working principle of optical fiber interferometric water level sensor, the interference principle of optical wave and the modulation principle of optical wave phase in the process of stress and strain of optical fiber are introduced from the theoretical point of view. The functional relationship between the water level and the phase change of light wave is derived. Based on the analysis of the coupling characteristics of the 3 ~ (3) coupler, the conclusion that the output light has a phase difference of 2 ~ (3) is obtained. According to this characteristic, a discriminable Mach-Zehnder interferometric optical fiber water level detection system is established. Then, in view of the signal demodulation module is an important part of the system, based on the completion of the experimental hardware preparation, a dynamic dual-threshold fringe count detection method is proposed for the signal demodulation of the system. At the same time, the resolution of the system is improved and the dynamic range of the sensor is reduced. The system combines the computer and hardware module with virtual instrument to realize the demodulation of phase signal and the real-time display of water level information. Compared with the traditional circuit counting method, the software demodulation method can reduce the production cost and shorten the production cycle of the system. It can also avoid the electrical noise from the hardware circuit and make the signal processing more flexible. Finally, the experimental results and signal analysis show that the linear correlation coefficient of the water level sensing system is 0.9991. Through the calculation and simulation, the system with the highest resolution of 1. 59 mm, is obtained, and the precision of the system is 0. 01, which reaches the expected precision index. It is proved that the software demodulation scheme of high precision water level detection system based on fiber-optic interferometry is feasible, and its broad application prospect is worthy of further study.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P731.25;P714.1
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