伪随机信号电法仪的抗干扰参数  

Anti-interference parameters of instrument for electrical prospecting using pseudo random signal

作　　者：罗延钟[1] 陆占国 王寒冰 孙国良[3] 高隆钦 LUO YanZhong;LU ZhanGuo;WANG HanBing;SUN GuoLiang;GAO LongQin(China University of Geosciences,Wuhan 430074,China;Beijing Orangelamp Geophysical Exploration Company Limited,Beijing 102200,China;Beijing University of Aeronautics and Astronautics,Beijing 100083,China)

机构地区：[1]中国地质大学,武汉430074 [2]北京桔灯地球物理勘探有限公司,北京102200 [3]北京航空航天大学,北京100083

出　　处：《地球物理学进展》2023年第1期474-483,共10页Progress in Geophysics

摘　　要：基于伪随机信号系统辨识的电法勘查仪器多试图借助于相关处理——计算大地(系统)输入信号(供电电流I(t))和输出信号(电位差ΔU(t))的互相关R_(I,U)(t)和自相关R_(I,I)(t)——以期提高获取大地阻抗的瞬变过程(冲激响应和阶跃响应)和/或频谱(频率响应)的抗干扰性能.笔者先前的研究结果表明,仅在偏移时间t小于位宽Δt,特别是在零偏移时间,互相关R_(I,U)(t)和自相关R_(I,I)(t)函数值较大时才有较强的抗干扰能力;而时间偏移t大于位宽Δt时,相关函数值非常小,易受干扰而畸变.利用全周期相关函数值计算大地(系统)时间响应和频率响应的伪随机相关辨识的抗干扰性,并不理想.在电磁干扰较大或信噪比较低(近于或小于0 dB)时,不能取得可靠的时间响应和频率响应数据.基于上述情况,本文提出仅利用零偏移时间的互相关和自相关函数值R_(I,U)(0)和RI,I(0),获取具有高抗干扰性能的导电和激电参数.文中给出了这些抗干扰参数的具体算法,并列举仿真模拟和野外观测数据,证明它们的实际抗干扰能力.The instruments for electrical and electromagnetic prospecting using pseudo random signal have tried to Improve anti-interference ability for geting the earth frequency response or/and time response by means of correlation processing——to calculate the auto-correlation R_(II)(t)and cross-correlation R_(IU)(t)of the input signal(strength of supply current I(t))and output signal(potential difference ΔU(t)).Previous research by the authers suggests that just in the condition of the offset time is litter than the bit width of the pseudo random signal,especially at the zero offset time,the function value of auto-correlation R_(I,I)(t)and cross-correlation R_(I,U)(t)are large,it has strong anti-interference ability;and when the offset time great than the bit width,the function value of auto-correlation R_(I,I)(t)and cross-correlation R_(I,U)(t)are very small,susceptible to interference and distortion.The anti-jamming capability of the“pseudo random correlation identification”,which using the correlation function value of the whole cycle,to get the earth frequency response or/and time response,is clearly not ideal.In the condition of high electromagnetic interference or low SNR,can’t get reliable data of earth frequency response or/and time response.Based on above-mentioned condition,this paper proposes to use only the function value of auto-correlation R_(I,I)(0)and cross-correlation R_(I,U)(0)at the zero offset time,to obtain conductive and IP parameters with high anti-interference performance.The concrete algorithm of these parameters and some simulation and field observation data,which proved actual anti-jamming ability of these parameters are given in this paper.

关 键 词：电法勘查 观测仪器 伪随机信号 抗干扰参数 

分 类 号：P631[天文地球—地质矿产勘探]