Distance measurement method for frequency modulation continuous wave radar system

Abstract

The invention provides a distance measurement method for a frequency modulation continuous wave radar system. The method comprises the following steps: Step S1. discrete intermediate frequency signals collected by the frequency modulation continuous wave radar system are subjected to discrete Fourier transformation to find out the spectral line number km of the discrete spectrum maximum and the spectral line number kc of the discrete spectrum second-maximum; Step S2. the procedure goes to Step S4 if the number kc=km-1, and goes to Step S3 if kc is not equal to km-1; Step S3. the frequency domain in the discrete intermediate frequency signals is shifted to the right based on delta f / 2 to make the spectral line numbers km and kc after shifting meet kc=km-1, wherein delta f is the frequency resolution of the discrete Fourier transformation of the N point; Step S4. the discrete intermediate frequency signals are subjected to discrete Fourier transformation by reducing one sampling point to find out the spectral line number k'm of the discrete spectrum maximum; Step S5. the spectral line number k'm of the discrete spectrum maximum is judged, Step S4 is repeated if k'm=km, and the procedure goes to Step S6 if k'm is not equal to km and k'm=km-1; and Step 6. the distance interval (R1, R2) between the radar and the target is worked out according to the sampling point number of the discrete Fourier transformation and distance relational expression, and the distance value between the radar and the target is R'=(R1+R2) / 2.

Description

technical field [0001] The invention belongs to the technical field of frequency modulation continuous wave (FMCW) radar system ranging, and is particularly used for non-contact ranging due to the influence of environmental factors and the like. The method can be used for distance measurement calculation of liquid level gauge, and also can be used for distance measurement calculation of material level, and has the advantages of high calculation accuracy, small calculation amount, and good anti-noise performance. Background technique [0002] Chirp continuous wave radar has many advantages that other radars do not have: no distance blind spot, high range resolution, and low radiated power. Measuring distance with radar is non-contact measurement, so it will not cause damage to the target object, and can be used in many special environments to achieve high-precision measurement. The principle is: send a linearly transformed frequency-modulated continuous wave to the target, r...

AI Technical Summary

Problems solved by technology

[0005] The most important technical defect of the existing technology: Since ZFFT, CZT and zero-padding spectrum refinement need to perform discrete Fourier transform, the spectral amplitude of non-integer multiples is calculated by interpolation, but the spectral line amplitudes near the maximum value are quite different. Small, due to the influence of spectrum leakage and noise on the spectrum, it is easy to misjudgment the maximum value and affect the accuracy of the algorithm. For this reason, the present invention provides a method for measuring the frequency modulation continuous wave radar system

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