本文对所研制的半导体激光自混合测速系统在4.06 ~475.3 mm/s 的速度范围内获得了1%左右的速度精度进行了报道。同时，我们针对激光自混合测速系统的试验装置对速度测量精度进行系统研究，重点讨论了激光光谱谱宽、速度分布、散斑、电子学线路对多普勒信号展宽的影响。分析结果表明，散斑信号在待测速度较小时所造成的多普勒信号展宽是激光自混合测速系统测速精度下降的主要原因。采用提高采样时间以及改进电子学处理系统的方式，是提高激光自混合测速系统精度的一个较好途径。

The velocity measurement accuracy 1% from 4.06 ~475.3 mm/s and analysis of accuracy for Laser Doppler Velocimers (LDVs) based on self-mixing effect are reported. We specifically address the study of broadening of Doppler frequency due to laser spectrum, velocity distribution, speckle pattern and electronics. It can be concluded that the velocity measurement error is mainly caused by speckle patterns especially with small velocity. Extension of sampling time and selecting proper signal processing circuits is a good solution for improving velocity measurement accuracy.