时间域编码电磁勘探方法研究

为了抑制空气波干扰，该文提出时间域编码电磁方法，采用伪随机编码信号作为激励信号，基于同步记录的编码信号和接收电压信号，通过时间域反卷积信号复原方法获得含有异常体信息的大地冲激响应，同时分析了时钟频率与编码长度的选择依据。该方法进行了外场实验验证，对比实验结果表明:该方法通过降低时钟频率与增大编码长度可显著提高电磁数据的信号质量，抑制空气波干扰，有效识别地下异常体信息。 

Investigation on Time Domain Coded Electromagnetic Exploration Method

To suppress airwave interference, a time-domain coded electromagnetic exploration method is proposed with Pseudo-Random Binary Sequences (PRBS) code as the source signal. Based on the PRBS code and receiving voltages, which are recorded simultaneously, the impulse response of the earth can be obtained by the time-domain deconvolution signal recovery method, and the target information is effectively contained in the impulse response. The selection methods of clock frequency and code length were analyzed and field experiments were carried out, which demonstrated that the signal quality of the EM data could be improved by decreasing the clock frequency, or increasing the code length. The proposed method could greatly suppress the airwave interference and effectively identify underground anomalies.