基于尾流激光雷达的能量对消式大动态接收技术

Large dynamic range receiving technology with energy consumption based on wake lidar

水下尾流激光雷达在近场就已开始与水体发生了激光的多次散射,很容易导致接收系统因动态范围不够而饱和,其反向恢复时间一般长达10~2ns级,影响远场信号接收.本文针对此问题分析了激光水体后向光散射强度衰减规律,自主研发了一种能量对消式水下激光雷达前端接收系统.该系统通过在近场强信号尖峰上叠加一个高速反向瞬态对消电流抑制接收系统饱和,之后将两信号融合,还原真实回波信号波形.分析了技术难点并给出了解决方案,讨论了瞬态对消电流的生成时刻对强度的影响规律.经实测与分析,该系统对消电流脉宽为5 ns,幅度控制步进为122 nA,幅度调节范围为135—360μA,成功实现了对近场强散射的抑制.该系统完全可以满足尾流激光雷达大动态探测的需要.

The multiple scattering of underwater lidar for wake happens in the near field,which leads ordinary receiving system to be saturated due to lack of dynamic range.The receiving system recovery time is usually up to several nanoseconds,which affects the receiving of the far-field signal.For this problem,the attenuation law of laser back-scattering intensity by water is analyzed and a front-end receiver of underwater lidar with energy consumption is developed.A high-speed reverse transient cancellation current is superimposed on the strong peak of near-field part signal to prevent the receiving system from being saturated,thereby restoring the two signals to integrated returned signal waveform.The technical difficulties are analyzed and the solutions are presented.The influence of generation time of transient cancellation current on intensity is discussed.The results of measurement and analysis prove that the transient cancellation current is 5 ns in pulse width,its adjustable step of 122 nA and the adjustable range is 135-360 uA.The system suppresses the near-field strong scattering signal successfully and can meet the requirement for the underwater large dynamic range lidar for wake.