【作者】 王洪亮；

【导师】 董浩斌；

【作者基本信息】 中国地质大学 ， 地球物理工程， 2012， 博士

【摘要】 质子磁力仪是磁法勘探用以观测和采集磁场及其异常数据的仪器设备,它利用静态激发质子在地磁场内的larmor进动效应测量磁场。质子磁力仪探头输出的FID信号是一个信噪比比较低的且随时间按指数衰减比较快的信号,研究低信噪比高精度频率测量技术对提高仪器测量精度非常重要,特别是提高磁场测量精度方面,因此高精度频率测量算法是当今研究的热点。论文针对质子磁力仪FID信号特征及测频方法,主要研究了基于FFT、自相关、相关自适应、小波自适应、Chaos等基本算法的FID信号处理以及基于FDM、SVD、Prony等算法的FID信号处理。论文先是扼要地介绍了这些算法的理论,对FID信号的适用性进行了分析,然后分别基于这些算法对FID信号进行处理,给出了仿真实验结果,最后对测频改善情况进行了分析与对比,验证了算法的有效性和一致性。此外,文章还研究了质子磁力仪的原理与结构、FID信号信噪比与测频精度的关系以及FID信号外界干扰的抑制等。论文第一章绪论,介绍了本文研究目的与意义以及国内外研究现状,并给出了目前存在的问题,最后提出了本文的研究内容和拟解决的关键技术；而对质子磁力仪FID信号研究,必然要了解质子磁力仪的原理、结构等,因此,第二章简单介绍下仪器的原理、组成,并探讨了FID信号频率测量结构整体框图,为后续部分的研究与设计奠定基础；第三章研究了FID信号特征：分析了FID信号噪声背景、信号特性,探讨了直接测频方法和间接测频方法,并研究了频率变换。最后,本章主要研究了FID信号信噪比与测频精度关系,通过理论分析,推导了频率测量精度与信噪比间的大致关系表达式,为后文研究提供了保证；第四章基于基本算法对FID信号进行了处理。主要研究了FFT算法、Chaos算法、自相关算法、相关自适应算法和小波自适应算法,分析了它们的基本原理和适用性,分别基于这些算法对FID信号进行了处理。此外,根据不同的信噪比,对FID信号进行仿真实验,给出了实验结果,并对测频改善和算法的有一效性和一致性进行了分析；第五章研究了基于FDM算法的质子磁力仪FID信号处理。根据FID信号特性以及FDM算法的需求,对FID信号利用矩阵进行了数学建模,采用了Hilbert、Taylor变换等将实信号变成复信号,分四种情况对复信号进行矩阵建模及验证。接着,论文分析了FDM算法的基本理论和FID信号的适用性,并基于FDM对FID信号进行了处理,根据不同的信噪比,对FID信号进行仿真实验,给出了实验结果,最后对测频改善和算法的有效性和一致性进行了分析;第六章主要研究基于SVD算法的FID信号处理。SVD用于信号的降噪,要重构相空间、进行SVD分解和逆变换,以达到提取有用信号的目的。内此,本章在分析了SVD的基本理论和FID信号适用性的基础上,基于SVD算法对FID信号进行了处理。最后,论文根据不同的信噪比,对FID信号进行仿真实验,给出了实验结果,并对测频改善和算法的有效性和一致性进行了分析；第七章主要研究基于Prony方法的FID信号处理。论文分析了Prony的基本原理和FID信号的适用性,并进行了相关改进。接着基于Prony算法对FID信号进行了处理,根据不同的信噪比,对FID信号进行仿真实验,给出了实验结果,并对测频改善和算法的有效性和一致性进行了分析;论文的最后归纳了文章的成果、结论与主要创新点,并指出了存在的不足,为进一步研究提出了建议。更多还原

【Abstract】 Proton magnetometer is the equipment for the observation and acquisition of the magnetic field and its abnormal data, which uses the lannor precession effect of static excitation proton to measure magnetic fields.The FID signal of proton magnetometer probe, a relatively low signal-to-noise ratio, is attenuating as an exponential with time. So, the low signal-to-noise ratio and high-precision frequency measurement techniques plays an important role in improving the measurement precision, especially the accuracy.Thus, the algorithm of precision frequency measurement is a hot today.The paper focuses on the FID signal characteristics and frequency measurement method of proton magnetometer, mainly to the study of FID signal processing based on some algorithms, such as FFT, autocorrelation, wavelet, adaptive, Chaos,FDM, SVD, Prony method and so on. First, it briefly introduces the theory of these algorithms, the analysis of applicability of FID signal, and then achieves FID signal processing based on these algorithms and gives simulation results. Finally, the contrast of improvement of frequency measurement is analyed and simulated to prove the effectiveness and consistency of the algorithm. In addition, the paper also studies the principle and structure of a proton magnetometer, the relationship between FID signal-to-noise ratio and frequency measurement accuracy, and the suppression of FID signal interference.The first chapter of the paper introduces the purpose, the significance, domestic and foreign research background, then points out the current problems, finally concludes the research content and the key technology which will be solved;The proton magnetometer principle and structure is nesscery for studying proton magnetometer FID signal.Therefore, the second chapter of the paper briefly describes the structure of instrument, and discusses the overall block diagram of the the FID signal frequency measurement,which gives the foundation for the subsequent part of the study design;The third chapter studies the FID signal characteristics:analyzing the FID signal noise background, the signal characteristics, and discussing the direct frequency measurement and indirect frequency measurement method, then studying frequency conversion. Finally, this chapter mainly studies FID signal-to-noise ratio and the measured frequency accuracy relationship, through theoretical analysis, tryto get the expression of the relationship in order to provide a guarantee for later study;The chapter IV achieves the FID signal processing based on the conventional algorithms. It mainly studies FFT algorithm, Chaos algorithm, Auto-correlation algorithm, relevant adaptive algorithm and wavelet adaptive algorithm. After analyzing the basic principles and applicability of the FID signal, the FID signal based on these algorithms are processed respectively. Besides, depending on the signal-to-noise ratio of the FID signal, some simulation experiments are done and the experimental results are given to show the improvement of frequency measurement and the effectiveness and consistency of the algorithm;The fifth chapter studies the FID signal processing of proton magnetometer based on FDM algorithm. According to the FID signal characteristics and needs of the FDM algorithm, the FID signal matrix mathematical modeling is founded. Using the Hilbert, Taylor transform to make a real signal into a complex signal, four points of the complex signal matrix is discussed.Then, the paper analyzes the basic theory of the FDM algorithm and the applicability of the FID signal, and the FID signal processing based on FDM is done. Finally, depending on the signal-to-noise ratio of the FID signal, some simulation experiments are done and the experimental results are given to show the improvement of frequency measurement and the effectiveness and consistency of the algorithm;The sixth chapter mainly studies the FID signal processing based on SVD algorithm. SVD is used to reduce signal noise, reconstruction phase space, singular value decomposition and inverse transform, in order to extract useful signal. Therefore, after analyzing the basic theory and applicability of the FID signal, this chapter processes FID signal based on SVD algorithm. So, depending on the signal-to-noise ratio of the FID signal, some simulation experiments are done and the experimental results are given to show the improvement of frequency measurement and the effectiveness and consistency of the algorithm;The seventh chapter mainly studies the FID signal processing based on Prony method. The paper analyzes the basic principles of the Prony method, the applicability of the FID signal, and then some improvements of method is got. Besides, depending on the signal-to-noise ratio of the FID signal, some simulation experiments are done and the experimental results are given to show the improvement of frequency measurement and the effectiveness and consistency of the algorithm;The last chapter summarizes the results, conclusions and major innovation of thesis. The shortcomings and suggestions for further research are pointed out.更多还原