Research on Real-Time Laser Range Finding System

Abstract:

Phase shift laser range finder, as a large-scale, high-precision measurement method, is widely used in industrial and military fields. The traditional laser range finder can not meet the need of real-time, high resolution measurement because of its low anti-jamming capability and time-consuming measurement. Owing to this, multi-channel transmitting and receiving system for phase shift laser range finder based on parallel DSP was designed. Multi-frequency modulation laser can be transmitted and received at the same time, improving the measurement speed and avoiding the wrong data fusion because of target moving. The distance was got by measuring the phase difference between the measurement signal and reference signal, and the Doppler velocity of the target is got by measuring the measurement signals frequency, The measurement signals reference signals were acquired by parallel AD convertors, the phase difference between them was calculated adopting all-phase FFT(apFFT). A new frequency correction method was proposed according to the amplitude spectrum acquired by apFFT, Amplitude spectrum is expanded into Taylor series and the correction value of frequency is calculated by relationship of spectrum lines. Monte Carlo simulation results proved that the new frequency correction method had higher resolution and better stability than Rife method and centro-baric method. The experiments is implemented on a precision guide of 3m-long, on the condition that the sampling frequency of AD converter is 937.5KHz, the apFFT transform point number is 4096, distance and velocity results can be obtained each 10ms, experiments prove that the distance measurement standard deviation better than 0.09mm and the velocity measurement standard deviation better than 0.022m/s are obtained. The system can meet the need of high accuracy ,real-time distance measurement of moving target.

• Periodical: Applied Mechanics and Materials (Volumes 347-350)
• Pages: 1053-1058
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.347-350.1053
• Online since: August 2013
• Authors: Fang Xiu Jia, Ji Yan Yu, Zhen Liang Ding, Feng Yuan
• Keywords: apFFT Spectrum Correction, Laser Range Finder, Multi-Frequency Modulation, Parallel DSP

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