摘要
与常规互相关法辨识系统脉冲响应的方法不同,本文提出了一种直接由循环互相关法辨识系统频率特性的方法,用于地球物理谱激电法勘探.具体方法是:采用编码源信号为激励波形,运用循环互相关法可恢复出系统的频率响应.仿真计算结果表明:本方法在强干扰条件下可高精度辨识出待辨识系统的频率响应,较高的采样率和叠加次数可有效提高测量精度.野外谱激电法实验中,采用编码源激发,中间梯度装置,最大供电极距5200 m,接收电极距20 m,阵列式同步采集,供电电流8 A条件下,在强干扰工作区获得了可靠的视电阻率、相对相位和金属因素剖面异常.通过实测数据分析:该方法有助于提高系统频率响应的辨识精度,且有很高的频率分辨率;增加采样周期数是在强干扰区获得高质量数据的有效途径.
In this paper,we proposed a method to identify the frequency response of the system directly by the circular crosscorrelation method,which is different from the conventional method of identifying the impulse response of the system,and can be used in geophysical spectrum induced polarization method. The specific method is： using the coded source signal as the excitation waveform,the frequency response of the system can be retrieved by the circular cross-correlation method. The simulation result shows that this method can identify the frequency response of the system with high precision under the conditions of strong interference,and high sampling rate and multi-periods superposition can effectively enhance the measuring precision. In the field experiment of spectrum induced polarization method, using the coded source excitation,with central gradient array and the maximum AB dipole distance is 5200 m,and the receiving dipole distance is 20 m.Using twenty-five receivers recorded electric field synchronously in time sequence with inline array. With supply current of 8 A,in strong interference region we got the reliable apparent resistivity,relative phase and the metallic factor profile anomaly. Through the field data analysis： this method is helpful to improve the identification accuracy of the system frequency response,and has a high frequency resolution; The results also suggested that multiperiods superposition is the effective way to obtain high quality data in strong interference area.
出处
《地球物理学进展》
CSCD
北大核心
2017年第3期1393-1398,共6页
Progress in Geophysics
基金
相关辨识技术在谱激电中的应用研究(41374185)资助
关键词
编码源电磁法
相关辨识
频率响应
逆重复M序列
循环互相关
coded source electromagnetic method
system identification based correlation method
frequency response
the inverse repeated M-sequence
circular cross correlation
