少光子灵敏度精密激光测距方法及验证

Estimation and verification of high-accuracy laser ranging on several photons

针对传统线性探测激光能量需求高、光子计数难以区分信号和噪声的特点,提出了一种基于少光子的高精度激光测距方法。利用硅光电倍增管(Silicon Photomultiplier,SiPM)作为回波探测器,并对脉冲测距系统的回波响应模型、噪声特性以及测距精度进行分析。搭建了实验验证系统,实现了在激光波长为532 nm、能量为10 nJ的条件下,对107.86 m处的面目标进行测距。实验结果表示,系统的噪声为随机分布,且噪声幅度不超过3个像元同时响应量级,鉴别阈值略大于该值时,即可清晰地分辨出信号和噪声;对于包含32个光子的回波信号,探测器中发生雪崩像元的个数约为4个,此时系统测距精度达到3σ=3 cm。

A new high-accuracy laser ranging technology based on several photons was mentioned and verified, according to traditional linear detection needing high laser energy and photon counting detection hard to distinguish the avalanche events generated by signal or noise. Silicon Photomultiplier was used as echo detector, making analysis of the echo response model, noise characteristics and ranging accuracy.Laser ranging system was set up to measure target of the 107.86 m at laser wavelength of 532 nm and energy of 10 nJ. Experimental verification result indicates that the noise is a random distribution, which maximum magnitude equals to three pixels fired at the same time. When threshold is set above that,noise and signal can be clearly distinguished. For echo signal containing 32 photons, about four pixels are fired. Meanwhile, ranging accuracy of the system is up to 3 cm at 3 sigma.