Two-step laser ranging method and system based on pseudo-random code modulation

The invention discloses a two-step laser ranging method and system based on pseudo-random code modulation, and the method comprises the steps: carrying out the correlation of a receiving signal and a transmitting signal through transmitting a low-frequency pulse, taking a position corresponding to a correlation peak as a rough measurement distance, and selecting a high-frequency pulse according to a rough measurement result for fine measurement, thereby obtaining a final fine measurement distance; therefore, the problem that the maximum unambiguous distance is limited by high repetition frequency is solved, and the problem that echo signals are difficult to extract under the low signal-to-noise ratio is solved. 本发明公开了一种基于伪随机码调制的两步法激光测距方法及系统，通过发送低频脉冲对接收信号和发送信号做相关，相关峰对应位置为粗测距离，根据粗测结果选择高频脉冲进行细测，得到最终细测距离；从而减小了高重复频率对最大不模糊距离的限制问题，以及低信噪比下回波信号难以提取的问题。