使用格雷互补码脉冲序列作为光时域反射仪（OTDR）探测光脉冲，并结合相关处理，可以在不影响空间分辨率的前提下提高动态范围，增加有效的测量距离。文章将格雷互补码应用于便携式OTDR，对强噪声环境下信噪比改善特性进行了分析和仿真，并通过实验验证了理论的正确性。通过数字平均进行强噪声抑制，再相关处理能获得更好的响应曲线。在编码长度为256时，通过先数字平均,再相关运算，便携式OTDR动态范围可提高9dB。

The dynamic range of an optical time domain reflectometer (OTDR) can be improved without sacrificing the space resolution by using correlation technique employing Golay complementary code. In this paper, Golay complementary code was applied in protable OTDR to analyze and simulate the improvement of SNR under strong noise environment. The effect of the theory is validated through experiments. A better response curve can be obtained first by using numeral average to suppress the strong noise and then correlation. With this method, the dynamic range of portable OTDR improves by 9dB with a length of 256 Golay complementary code.