外差探测激光多普勒雷达由于具有测速精度高和可辨别速度方向等优点而广泛应用于测风、流体测速以及 着陆导航等方面。对外差激光多普勒雷达的测速原理、误差来源和系统噪声进行了分析，并给出了系统的信噪比和探 测精度的仿真结果。搭建了全光纤外差探测激光多普勒系统。用研制的高精度运动目标模拟器开展了相关测速 实验。实验结果表明，速度测量精度优于6.7 cm/s，而且与速度大小基本无关，这与仿真分析结果相一致。

Heterodyne detection laser Doppler radars are widely used in wind measurement, fluid speed measurement and landing navigation etc because of their high measurement accuracy and good velocity direction discrimination ability. The operation principle, error sources and system noise of a heterodyne detection laser Doppler radar are analyzed and the simulation results of signal-to-noise ratio and detection accuracy of the system are given. An all fiber heterodyne detection laser Doppler radar system is developed. The speed measurement experiment is made on it by using a high precision motion target simulator. The experimental result shows that its measurement accuracy is better than 6.7 cm/s and is independent of velocity. This result is consistent with the simulation result.