相干度分析用于强干扰背景下多频激电信号处理

摘要

Data processing in strong interference environment was investigated and coherence analysis was applied to do it. The coherence of potential difference and transmitting current for each period is relative to the data quality and the signal-to-noise ratio (SNR). SNR of data with coherence more than 0.5 can be high enough, which can be used for the subsequent data processing and resistivity calculation. In contrast, SNR of data with coherence less than 0.5 even close to 0 can be low and the IP signal is submerged by noise, which cannot be used for subsequent data processing. The effectiveness of our processing approach was demonstrated by showing examples of a data acquired in Gansu Province, Baiyin was demonstrated. The threshold is set and the observation data of high quality can be extracted to obtain more accurate calculation results of complex resistivity spectrum. For the survey point with strong interference, The error of complex resistivity phase is reduced from 1000 m/r to 150 m/r and error of complex resistivity phase at high frequency is reduced to 40 m/r. The error of complex resistivity amplitude is reduced from 100% to 10% approximately. This method is effective.%提出将相关度分析用于强噪声环境下的m序列多频激电信号处理。多频激电各周期电压电流数据的相关度与数据观测质量、信噪比存在明显的对应关系。当相关系数在0.5以上时，数据信噪比较高，可用于后续数据处理与复电阻率计算；而当相关系数在0.5以下甚至接近于0时，信噪比很低，有用信号已基本被噪声淹没，无法用于后续数据处理。将相关度分析应用于甘肃白银矿区实测数据，设置阈值提取出质量较高的观测数据用于后续数据处理，从而获得更为准确的复电阻率计算结果。对于干扰特别严重的测点，可使复电阻率相位误差由1000 mrad以上降至150 mrad以下，高频相位误差降至40 mrad以下。幅值误差由100%以上降至10%以下，应用效果较好。