摘要
利用逆重复M序列伪随机信号良好的自相关特性,提出相关检测地电传输特性的编码电磁勘探法.分析了编码电磁测深原理及参数提取方法.同时记录发送电流信号和多收发距电磁场响应,对源信号和场信号进行相关运算,解卷积分离接收系统响应后可得到大地的频率特性或时间特性,以此实现地电断面的精细探测.在时间域,大地冲激响应和阶跃响应含有丰富的地电信息.通过冲激响应的峰值时间或阶跃响应的晚期渐近值可估计地电阻率分布.基于层状模型的大地冲激响应和阶跃响应正演计算结果表明,编码电磁测深法对大埋深薄层目标体有精细的分辨能力.可应用于能源、矿产资源、水资源、环境地质及工程地质勘察,有良好的应用前景.
Coded source electromagnetic sounding method is proposed based on cross correlation detection theory. The source current is coded by inverse repetitive M pseudo-random signal sequence for its good autocorrelation properties. By cross-correlation of the coded current and simultaneously received electromagnetic field response, the earth transform function is recovered. This is the foundation of coded source electromagnetic sounding method. The frequency characteristics or time characteristics of the earth can be retrieved from the transform function. In the time domain the impulse response and step response contain rich information of subsurface. The earth resistivity distribution can be estimated by the peak time of impulse response or the late asymptotic value of the step response. The results of impulse response and step response of the layered earth model forward calculation show that the coded source electromagnetic sounding can finely detect out the thin body at large depth. This method can be applied to investigation of energy, mineral resources, water resources, environmental geology and engineering geology, and has a good prospect for deep earth exploration.
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2012年第1期341-349,共9页
Chinese Journal of Geophysics
基金
西部交通项目(200731881262)
中央高校基本科研业务费专项资金(CHD2009JC027)
长安大学基础研究支持计划专项基金
西部矿产资源与地质工程教育部重点实验室开放基金联合资助
关键词
逆重复M序列伪随机信号
电磁法勘探
互相关辨识
冲激响应
阶跃响应
Inverse repetitive M pseudo-random binary sequence, Electromagnetic exploration,Cross-correlation identification, Impulse response, Step response
