The negative pulsed downlink communication system is used to send surface control commands to the downhole rotary steering tool at thousands of meters, which is a significant part of the current rotary steering technology. At present, the transmission efficiency of negative pulsed downlink communication is very low, and only simple control commands can be transmitted in a few minutes, which limits the development of rotary steering technology with complex control functions. To improve the transmission rate of the downlink system, the downlink pulse width needs to be shortened. However, due to the influence of signal transmission characteristics, the waveform of a narrow pulse width signal will be severely distorted, which increases the difficulty of decoding the downlink signal. Therefore, a decoding method based on pattern recognition for negative pulsed downlink signal with narrow pulse width is proposed in this paper, which establishes a Euclidean distance matrix model between similar characteristic signal segments on the rising or falling edge of the downlink signal, the pulse coding timing of among the signal segment with each rising or falling edge is analyzed, the decoding and recognition of the downlink instruction are achieved, which solves the problem of large timing deviation in decoding the downlink signal with a current threshold method. The experimental results show that the method proposed in this paper can achieve accurate decoding of the 6 s pulse width downlink signal. Compared with the threshold method, it can be seen that the decoding accuracy of the method proposed in this paper can be greatly improved, and the smaller the signal pulse width, the more significant the advantage.

负脉冲下行链路通信系统用于将表面控制命令发送到数千米的井下旋转导向工具，这是当前旋转导向技术的重要组成部分。目前，负脉冲下行通信的传输效率很低，几分钟内只能发送简单的控制命令，限制了具有复杂控制功能的旋转转向技术的发展。为了提高下行链路系统的传输速率，需要缩短下行链路脉冲宽度。然而，由于信号传输特性的影响，窄脉宽信号的波形将严重失真，这增加了解码下行链路信号的难度。因此，提出了一种基于模式识别的窄脉冲负脉冲下行信号解码方法，在下行信号的上升沿或下降沿建立相似特征信号段之间的欧氏距离矩阵模型。通过分析每个上升沿或下降沿的信号段之间，对下行指令进行解码和识别，解决了当前阈值法解码下行信号时时序偏差较大的问题。实验结果表明，本文提出的方法可以对6 s脉宽下行信号进行准确解码。与阈值方法相比，可以看出本文提出的方法的解码精度可以大大提高，