Beat frequency signal nonlinear correction method in FMCW distance measurement system

Abstract

The invention discloses a beat frequency signal nonlinear correction method in an FMCW distance measurement system, solves the problem of low signal-to-noise ratio caused by influence of frequency modulation nonlinearity on nonlinear correction by means of phase comparison of an auxiliary interferometer in the prior art, and belongs to the technical field of signal processing. The method comprisessteps that S1, Hilbert transform of signals of an auxiliary interferometer is carried out to acquire phase information of the signals of the auxiliary interferometer, the phase information is utilized to acquire an orthogonal basis used for nonlinear correction, and the orthogonal basis comprises frequency modulation nonlinear information; and S2, a measurement interferometer signal is sampled, and the measurement interferometer signal is converted by utilizing the orthogonal basis in the step S1 to finish nonlinear correction. According to the invention, the auxiliary interferometer is usedfor sampling the light source signal, the signal of the auxiliary interferometer is used as the orthogonal basis used in the spectral analysis method to replace the original linear phase orthogonal basis to carry out spectral analysis on the measurement path signal, and the influence caused by frequency modulation nonlinearity and light source mode hopping can be effectively eliminated.

Description

technical field [0001] The invention relates to a signal nonlinear correction method, in particular to a FMCW laser radar beat frequency signal nonlinear correction method, which belongs to the technical field of signal processing. Background technique [0002] In order to meet the needs of high-precision and high-speed measurement technology, a variety of different light sources are used in the laser FMCW (Frequency Modulated Continuous Wave, Frequency Modulated Continuous Wave) distance measurement system. has a direct impact. The frequency sweep bandwidth of the light source directly affects the measurement accuracy, and the frequency sweep speed also directly determines the measurement speed of the system. When the light source is swept with a higher bandwidth, such as figure 1 As shown, its beat frequency is proportional to the measured distance, correspondingly, a more precise peak will be formed on the spectrogram, as shown in figure 2 As shown, by measuring the f...

AI Technical Summary

Problems solved by technology

[0006] Aiming at the problem of low signal-to-noise ratio due to the influence of frequency modulation nonlinearity on the existing non-linear correction of phase comparison by means of an auxiliary interferometer, the present invention provides a non-linear correction of beat signal in an FMCW distance measurement system that improves the accuracy of beat signal spectrum analysis method

Images