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Frequency modulated continuous wave (FMCW) laser interferometry is very sensitive to optical path drift, and a small length drift will lead to a great measurement error in the ranging result. In order to improve the anti-interference ability of the system and realize the large-scale, high-precision absolute distance measurement, the influence of environmental vibration on the frequency-modulated continuous wave laser ranging is analyzed, and a vibration error compensation method based on the superposition of the reverse frequency sweep signal is proposed. Simulation and experimental results show that this method can effectively improve the spectrum offset, distortion and broadening of the measurement signal caused by the optical path drift caused by vibration. Within the measurement range of 43m, the system's ranging resolution and measurement stability have been significantly improved after vibration error compensation. The measurement resolution is very close to the theoretical value, and the measurement standard deviation is stable within 9μm. The method proposed in this paper can realize the compensation of optical path drift without real-time measurement of vibration, and improve the anti-interference ability of large-scale FMCW laser ranging system without increasing the system complexity.
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