为了解决传统光学测速技术需要添加示踪粒子的局限，发展了采用固体石英法布里-珀罗标准具检测流场固有分子瑞利散射光的多普勒频移来测量流场速度的技术。介绍了该技术的工作原理，主要分析了标准具性能参数、环境温度变化对系统测速性能的影响。建立了空间分辨的多点测速系统，通过光路设计，解决了环境温度变化对测量准确性的影响和提高了瑞利散射信号收集强度。通过高精度的数据处理方法，获得了马赫数1.5 喷管出口自由射流的的空间多点速度分布。结果表明，建立的测速系统和数据处理方法能够实现流场速度的精确测量。

The velocity of gas flow field is measured by using Fabry–Perot etalon to detect the Doppler frequency shift of molecular scattering. The working principle of velocity measurement system is introduced. The effects of performance of Fabry–Perot etalon and change of environmental temperature on the velocity measurement are analyzed. The multi-point velocity measurement system is set up. The unshifted incident laser signal and the shifted Rayleigh scattered signal are recorded simultaneously in order to eliminate the effect on the velocity measurement when the positions of interference fringes are changed due to the change of environmental temperature. A couple of large aspherical lens are used to enhance the taking intensity of Rayleigh scattering signal. Through high precision data transform means, the multi-point velocity results of high speed cold crossflow are obtained. The research results show that this method has the capability for velocity measurement of gas flow field with high dependability.