小飞镖的折法
摘要
基于到达时间差法的震源定位研究与实现
当前，震源定位的应用十分广泛，涉及到微震监测、岩体破裂、爆破位置确定、管道裂纹定位以及煤矿安全等领域，若能预先掌握震源位置信息，则可以避免这些突发情况带来的灾害，进而减少损失。到达时间差法是一种基于时延估计的定位模型，常用来确定目标的位置。该模型具有定位准确等特点，在一些工程领域中大量应用。
本文以地震动信号为研究对象，探讨震源定位的问题。从地震动信号特征分析、信号的预处理和时延估计、震源定位及位置修正等几方面进行研究，具体内容如下：
由于大地介质成分复杂，我们首先通过经验模态分解和Hilbert变换对振动信号进行处理，得出不同的Hilbert谱，并基于Hilbert谱对地震动信号的时、频域以及能量特性进行分析，对比不同情况下信号的波形及频谱，进而讨论地震动信号的衰减规律。比较几种常见的小波基函数和阈值估计方法，然后利用小波阈值方法对振动信号的背景噪声进行消噪处理。对于信噪比较低时，互相关方法很难提取到准确的时延估计问题，采用一种最大似然估计窗函数的广义互相关方法进行时延估计，并实验验证该方法的有效性。
针对经典Chan定位算法得到较差定位结果的情况下，牛顿优化方法容易发散导致算法失效这一问题，提出一种修正特征值的方法将病态矩阵正定化，通过引入步长因子来提高迭代速度，使每次迭代沿下降方向的同时尽快收敛。通过实测数据验证，改进后的方法可避免初始值偏差大导致迭代发散的问题，并利用均方差对Chan算法和本文的方法进行定位性能比较。
完成了多传感器数据采集系统的设计，包括硬件采集和上位机软件的编写两部分。计算了试验场地的波速，设计了不同情况下的多组震源定位实验，对定位结果进行讨论，最后分析可能引起定位偏差的原因。
关键词：
时延估计，时频分析，牛顿迭代，数据采集，震源定位
I
Abstract
Rearch and Implementation of Vibration Source Localization Bad on TDOA
Measurement
At prent, the application of vibration source localization is very extensive, involving the microismic monitoring, rock rupture, blasting position determination, pipeline crack localization and coal mine safety and other fields, if you can get the location information in advance, you may avoid the unexpected disasters, and reducing loss. Time difference of arrival method is a localization model bad on time delay estimation, which is often ud to determine the position of the target. The model has the characteristics of accurate positioning, and have a large number of applications in any engineering fields.
In this paper, ismic signal as the object of study, to explore the problem of vibration source. This paper studies the characteristics of ismic signal, the preprocessing of signal and the estimation of time delay, the vibration source localization and its correction. The details are as follows:
Due to the complex composition of the earth medium, we first process the ismic signals by empirical modal decomposition and Hilbert transform, and obtain different Hilbert spectra. Bad on the Hilbert spectrum, the time-frequency and energy characteristics of the ismic signals are analyzed. The waveform and the spectrum of the signal, and then discuss the attenuation of the ismic signal. Some common wavelet basis functions and threshold estimation methods are compared, and then the background noi of the vibration signal is denoid by the wavelet threshol
d method. For the low SNR, the cross correlation method is difficult to extract the exact time delay estimation problem. The generalized cross correlation method of the maximum likelihood estimation window function is ud to estimate the delay and verify the effectiveness of the method.
For the classical Chan localization algorithm has poor results orientation, Newton optimization method of divergence leading to this algorithm failure, the paper prents a method of modifying the characteristic values of the ill conditioned matrix II
过春节的习俗is positive definite, to improve the speed of iteration by introducing the step factor, so that each iteration along the descent direction and convergence as soon as possible. The experimental results show that the improved method can avoid the problem of the divergence of the initial value, and the performance of the algorithm is compared with the Chan algorithm and the method in this paper by RMSE.
Completed the design of multi-nsor data acquisition system, including hardware acquisition and PC software design in two parts. The wave velocity of the test site is calculated, and veral ts of source localization experiments are designed. The results of the positioning are discusd. Finally, the reason of the positioning deviation may be analyzed.
Keywords:
Time delay estimation, time-frequency analysis, Newton iteration, data acquisition, vibration source localization
III
目录
第1章绪论 (1)
1.1 课题研究的背景及意义 (1)
1.2 课题的国内外研究概况 (2)
烟花女儿翻身记1.2.1 地震动信号分析及定位理论研究现状 (2)
陕西博物院1.2.2 源定位技术的国内外现状 (5)
1.3 本论文的主要工作 (7)
第2章地震动波理论基础及特性分析 (9)
产后病2.1 地震动波类型及特性 (9)
2.2 振动传感器及装置的选择 (10)
2.3 地震动信号特性分析及相关理论 (12)
2.3.1 地震动波的衰减 (12)打嗝不停是什么原因
2.3.2 基于希尔伯特-黄变换的时频分析 (12)
2.3.3 远近距离波形的对比研究 (17)
2.4 本章小结 (19)
第3章地震动信号的预处理与时延估计 (20)
3.1 小波去噪 (20)
3.1.1 小波阈值去噪原理 (20)
3.1.2 小波去噪性能分析 (23)
3.2 广义互相关时延估计 (25)
3.2.1 基于最大似然窗函数的广义互相关方法 (25)
IV
3.2.2 时延估计方法验证 (27)
3.3 本章小结 (28)
第4章基于Chan和牛顿迭代混合的震源定位优化方法 (30)
4.1 基于Chan算法的初始定位 (30)
4.1.1 Chan定位算法 (30)
4.1.2 定位算法的仿真 (32)
刘德华几个孩子4.2 基于牛顿迭代的优化修正方法 (34)
4.2.1 基于TDOA模型的牛顿迭代法 (34)
4.2.2 改进的牛顿迭代方法 (35)
4.2.3 定位算法的仿真 (37)
4.3 定位的结果评价标准 (39)
4.4 本章小结 (41)
第5章多传感器数据采集系统与定位实验 (42)
面包品牌
5.1 基于C ORTEX-M3内核处理器的数据采集 (42)
5.1.1 硬件模块介绍 (42)
5.1.2 数据采集系统硬件部分 (43)
5.1.3 数据采集系统软件设计 (45)
5.2 振动数据采集软件设计 (47)
5.2.1 LabVIEW (47)
5.2.2 数据采集上位机软件设计 (47)
5.3 实验过程及结果 (50)
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