半航空瞬变电磁接收机研制

发布时间：2018-10-31 07:43

【摘要】：矿产对人类的生产生活至关重要,随着国民经济飞速发展,各行各业对矿产资源的需求量日益增大。无人机半航空瞬变电磁法是近年来提出的一种新的勘查方式,其采用了地面发射、空中接收的模式,将地面瞬变电磁的大发射功率和航空电磁的空中大范围灵活接收的优势相结合,是一种高效的地球物理勘测方法。因此研发实用型的半航空瞬变电磁接收机系统,对于研究半航空瞬变电磁探测方法、提升我国矿产资源勘查能力、推广应用于生产实践具有重要意义。本文依托于国土资源部公益性项目“基于无人机的半航空瞬变电磁勘查技术研究”(项目编号:201311037),分析了半航空瞬变电磁法原理及信号特征,并对基于无人机的半航空瞬变电磁接收机关键技术进行研究。首先介绍了半航空瞬变电磁法的研究背景和瞬变电磁接收机的研究现状;其次,从理论上分析了半航空瞬变电磁信号特征及数据处理方法;剖析国内外半航空瞬变电磁或瞬变电磁仪器功能,综合分析半航空瞬变电磁接收机的功能需求和技术指标,研究了GPS同步技术和存储技术;然后针对半航空瞬变电磁信号的特点,提出了以FPGA和ARM作为逻辑和控制中心的半航空瞬变电磁接收机设计方案;在GPS同步技术的基础上,通过学习恒温晶振的漂移特点,设计了基于FPGA和恒温晶振的高精度秒脉冲同步系统;在信号采集上,通过前置低噪声差分放大器调理线圈传感器输出的微弱信号,使用∑-?型结构24位高精度A/D转换器进行数据采集;在数据存储上,通过ARM控制SD卡存储采集的数据,除了存储瞬变电磁信号数据外,同时根据后期数据处理的正反演需求,将GPS时间位置、线圈姿态和相对高度数据同步处理打包后存储。半航空瞬变电磁接收机一般采用连续采集方式进行数据采集,并采用本地方式进行数据存储。最后,为了验证接收机的性能,对半航空瞬变电磁接收机的各项性能指标进行测试分析,并进行了野外实验;通过分析测试结果可知,接收机的GPS同步精度达到100ns,信号的最小分辨率为50μV,接收机初步满足了采集半航空瞬变电磁信号的需求,但接收机的整体性能仍有待进一步提高。
[Abstract]:With the rapid development of national economy, the demand for mineral resources is increasing day by day. The semi-aeronautical transient electromagnetic method of UAV is a new exploration method proposed in recent years. It adopts the mode of ground launching and receiving in the air. It is an efficient geophysical survey method to combine the large transmitting power of ground transient electromagnetism with the advantage of large range flexible receiving in the air of aeronautical electromagnetic field. Therefore, the development of a practical semi-aeronautical transient electromagnetic receiver system is of great significance for the study of semi-aeronautical transient electromagnetic detection methods, the enhancement of mineral resources exploration capability in China, and the popularization and application in production practice. This paper is based on the public welfare project of Ministry of Land and Resources, "the Research of Semi-Aeronautical transient electromagnetic Prospecting Technology based on UAV" (item number: 201311037), and analyzes the principle and signal characteristics of semi-aeronautical transient electromagnetic method. The key technology of semi-aeronautical transient electromagnetic receiver based on UAV is studied. Firstly, the background of the semi-aeronautical transient electromagnetic method and the research status of the transient electromagnetic receiver are introduced, secondly, the characteristics of the semi-aeronautical transient electromagnetic signal and the data processing method are analyzed theoretically. This paper analyzes the functions of semi-aeronautical transient electromagnetic or transient electromagnetic instruments at home and abroad, synthetically analyzes the functional requirements and technical specifications of semi-aeronautical transient electromagnetic receiver, and studies the synchronization technology and storage technology of GPS. Then, according to the characteristics of semi-aeronautical transient electromagnetic signal, a semi-aeronautical transient electromagnetic receiver with FPGA and ARM as logic and control center is proposed. On the basis of GPS synchronization technology, a high precision second pulse synchronization system based on FPGA and thermostatic crystal oscillator is designed by studying the drift characteristics of thermostatic crystal oscillator. In signal acquisition, a low noise differential amplifier is used to adjust the weak signal output from the coil sensor, using 鈭，

本文编号：2301421