基于电流场理论的地下数字通信系统设计与实现

发布时间：2018-08-24 08:08

【摘要】：我国矿产资源丰富，，然而矿难事件频发。如果能够实现地下与地面的无线通信，将会极大地提高救援效率。目前我国还没有自主知识产权的矿井透地应急救援通信系统。矿难发生时，其他有线通信手段往往会发生中断，信号如何穿透地层实现与地下信息的双向传输问题是矿井无线应急通信的关键瓶颈技术。而采用电偶极子天线，基于传导电流场理论实现透地信息传输是解决该瓶颈问题的行之有效的方法之一。本文在分析国内外地下通信的研究背景下，选用具有天线体积设计小、对环境依赖性小的基于电流场理论的通信方式。首先，介绍传导电流场透地通信理论，分析信号传输的原理。建立该传输方式的数学模型，并构建基于MATLAB的软件仿真平台，分析传输距离、信号频率与电导率对信号传输的影响。然后，在实地环境中建立物理仿真模型，讨论传导电流、传输距离，电磁干扰以及噪声对信号传输的影响，并观察仿真图形，为后续的系统设计提供优化的参数。最后，在理论研究和软件仿真分析的基础上，选取具有频带窄、功率利用率高、抗衰落、可用非相干进行解调的π/4-DQPSK作为数字传输方案，设计了基于FPGA的电流场地下通信系统。重点编制了基于Verilog的π/4-DQPSK调制和解调程序，通过模块化实现调制解调过程，方便程序的修改和调试；研发了该系统的硬件实现平台（含发送、接收电路，小信号放大电路，功率放大电路）；此外还进行了变压器的设计，使天线的阻抗与功率放大器阻抗实现匹配，以完成大功率发送信号。整个通信系统从串口收发，对信号进行调制解调以及D/A、A/D控制均可通过软件编写实现，体现了软件无线电的思想。
[Abstract]:China is rich in mineral resources, but mine accidents occur frequently. If underground and ground wireless communication can be realized, rescue efficiency will be greatly improved. At present, our country still has no independent intellectual property right mine penetrating ground emergency rescue communication system. When mine accident occurs, other wired communication means will often be interrupted. The key bottleneck technology of mine wireless emergency communication is how to realize two-way transmission of underground information through the formation. It is one of the effective methods to solve the bottleneck problem by using electric dipole antenna based on the theory of conduction current field to realize the transmission of information through the earth. In this paper, based on the analysis of underground communication at home and abroad, we choose the current field theory based communication mode with small antenna volume design and less environmental dependence. Firstly, the theory of transmissible current field is introduced, and the principle of signal transmission is analyzed. The mathematical model of the transmission mode is established, and the software simulation platform based on MATLAB is constructed to analyze the influence of transmission distance, signal frequency and conductivity on signal transmission. Then, the physical simulation model is established in the field environment to discuss the effects of conduction current, transmission distance, electromagnetic interference and noise on the signal transmission. The simulation figure is observed to provide the optimized parameters for the subsequent system design. Finally, on the basis of theoretical research and software simulation analysis, 蟺 / 4-DQPSK with narrow band, high power efficiency, anti-fading and non-coherent demodulation is selected as the digital transmission scheme, and a current field underground communication system based on FPGA is designed. The 蟺 / 4-DQPSK modulation and demodulation program based on Verilog is mainly compiled, and the modularization and demodulation process is realized through modularization, which facilitates the modification and debugging of the program, and the hardware implementation platform of the system (including transmitting, receiving circuit, small signal amplification circuit, etc.) is developed. In addition, the transformer is designed to match the impedance of the antenna with the impedance of the power amplifier to complete the high-power transmission signal. The whole communication system receives and receives signals from serial port, modulates and demodulates the signals, and controls the D / A / A / A / D by software programming, which embodies the idea of software radio.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TN929.4

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