Multiple Combinational Algorithm to Adaptively Track and Detect Measurement While Drilling Electromagnetic Wave Signal
Fukai Li, Zhiqiang Yang, Yehuo Fan, Chun Hao, Guangdong Zhu, Yujian Jin, Juan Fang, Tianlu Li · 2018
Band-pass filter is frequently used in measurement while drilling (MWD) system of electromagnetic (EM) wave transmission, so as to remove out-of-band noise. However, such design will increase the error rate of decoding when dealing with non-stationary time varying signal and especially in-band signal. By studying features of EM-MWD transmission and channel noise jamming, a multiple combinational algorithm that can adaptively track and detect EM signal is proposed in this article. This algorithm is a combination of low-pass filtering, five-point triple smoothing, adaptive notch, adaptive cancellation and line enhancement, and it takes recursive least squares as its principle of adaptive tracking. As theoretical analysis and simulation show, such algorithm can effectively extract useful signal from noise-contaminated signal and reduce the bit error rate, which lays a good foundation for further decoding.