Speed and distance measurement method and device based on frequency modulated continuous wave radar

Abstract

The invention discloses a speed and distance measurement method and device based on a frequency modulated continuous wave radar. The method comprises the steps of S1, obtaining an echo signal of a target radar, executing the FFT of partial points, and preliminarily obtaining the frequency of a target; S2, acquiring target information detected by the target radar, predicting the current speed and distance of the target by using the acquired target information, and converting the current speed and distance into a corresponding frequency to obtain a target prediction frequency; S3, determining afrequency refining section according to the target prediction frequency and the frequency of the target obtained in the step S1, and performing frequency spectrum refining on the determined frequencyrefining section to obtain a real refining frequency of the target; and S4, calculating by using the real refining frequency of the target to obtain the final target speed and distance. The method hasthe advantages of simple implementation method, low operation complexity, high detection efficiency, high detection precision and the like.

Description

technical field [0001] The invention relates to the technical field of frequency modulation continuous wave (FMCW) radar measurement, in particular to a method and device for measuring speed and distance based on frequency modulation continuous wave radar. Background technique [0002] When speed measurement radars such as traffic speed measurement radars measure the speed and range of targets, they usually directly process the entire spectrum of the echo signal. The signal spectrum represents the distribution of signal energy in the frequency domain. FFT (Fast Fourier Transform, Fast Fourier Transform Lie transform) is the main method to extract spectral information, but the signal spectrum obtained after FFT transform can only represent the amplitude value of each equal point, but not the spectral information between each equal point, that is to say, it cannot be obtained Frequency, amplitude, and phase information between equal points, which will affect the analysis of th...

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Problems solved by technology

However, if the spectrum is refined directly by increasing the number of FFT points to obtain the frequency, amplitude, and phase information between equal division points, the computational complexity will be greatly increased and the calculation time will be increased.

[0004] For spectrum refinement, the common classical methods mainly include: complex modulation refinement method, Chirp-Z transform (CZT), FFT+FT refinement method, DFT (Discrete Fourier Transform) zero padding, etc., but the above-mentioned various methods have certain limitations. For example, the DFT method is the spectrum evenly distributed at N points on the Z-plane unit circle. It is difficult to realize, and only study a certain frequency band of the signal, requiring intensive sampling of this frequency band; CZT (Chirp-Z transform) uses spiral sampling for Z transform, and the specific process of CZT transform is as follows Figure 1, CZT helical bisection angle sampling is shown in Figure 2, by directly fixing a certain frequency within the frequency range, it CZT spectrum subdivision can achieve refined spectrum. Based on CZT, narrowband high-resolution analysis can be easily realized. However, direct CZT spectrum subdivision can only fix a certain section of spectrum in the frequency range. Usually, this frequency range is large. When the number of refinement points is small, the spectrum refinement effect is not obvious. When the number of refinement points is too large, the computational complexity will be greatly increased, and the calculation time will be greatly increased.

[0005] In summary, when the traditional speed radar uses FFT to process the entire spectrum signal, under the same computational complexity, each frequency domain point represents a higher frequency , the accuracy of the target distance and velocity information obtained is relatively low, and the target distance and velocity information cannot be obtained accurately. Although more accurate target information can be obtained through spectrum refinement technology, the direct use of traditional spectrum refinement technology is to select a section Refine the spectrum of a relatively wide range. Due to the consideration of measurement errors, the range is usually set larger, and the spectrum refinement effect is limited, and the accuracy of target detection cannot be ensured.

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