基于m伪随机序列的电磁法抗噪能力分析  

A study on the noise immunity of electromagnetic methods based on m pseudo-random sequence

作　　者：王显祥[1,2] 底青云[2] 王妙月[2] 邓居智[1] 

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,南昌330013 [2]中国科学院地质与地球物理研究所中国科学院页岩气与地质工程重点实验室,北京100029

出　　处：《地球物理学报》2016年第5期1861-1874,共14页Chinese Journal of Geophysics

基　　金：国家重大科研装备研制项目"深部资源探测核心装备研发"(ZDYZ2012-1)-05子项目"多通道大功率电法勘探仪";国防科工委科研项目(科工技[2013]969号)联合资助

摘　　要：电磁法在金属矿、油气资源等矿产的勘探中发挥重要作用,同时电磁干扰也越来越强,在强干扰区利用传统的抗噪方法很难再获取高信噪比信号.鉴于伪随机序列的抗噪能力,近年来国内正在掀起伪随机编码仪研制的高潮.伪随机序列的抗干扰能力与从伪随机响应中提取方法息息相关,本文介绍了两种最常用的提取大地脉冲信号的方法:第一种通过将时间域信号转到频率域,对电流归一化处理后,再转回时间域求取大地脉冲响应;第二种直接在时间域解Wiener-Hopf方程求取.研究表明,在无干扰情况下两种提取方法都可获得高精度大地脉冲信号.随后在具有噪声干扰的情况下,对两种方法提取结果的精度进行了对比分析,表明方法2的抗噪声能力明显优于方法1的,对造成这种状况的原因进行了解析.最后研究了提高伪随机序列抗噪能力的方法,主要包括提高伪随机序列阶数、针对不同噪音使用不同的编码方式、改变循环次数的方法等,以达到抑制噪声的目的.Electromagnetic methods play an important role in the exploration of metal ore mineral,oil and gas resources.It is very difficult to obtain a high signal to noise ratio with increasingly strong electromagnetic noise using conventional anti-noise methods.In recent years,the pseudo random sequence attracts a lot of attention because of its anti-noise performance.This paper describes two common methods used to extract the impulse response from the pseudorandom sequence response.Studies have shown that the two methods are capable to get highprecision impulse response without noise.The extraction accuracies of the results using the two methods were compared with data contained in the noise,that shows that the results of method 2is better than 1,then the reasons for this situation was analuzed.Finally,a study is made to improve the ability of the anti-pseudo-random sequence of the methods,including to improve theorder of the pseudo-random sequence,use a different encoding,change the number of cycles in order to achieve the purpose of noise suppression.

关 键 词：伪随机序列 电磁法 抗噪分析 

分 类 号：P631[天文地球—地质矿产勘探]