Detection method of surface water velocity based on chirp-z transformation

Abstract

A method for detecting surface water flow velocity based on Chirp-Z transformation, comprising the steps of: inputting a Doppler radar signal, the Doppler radar signal originating from the echo of a continuous wave radar, and a baseband after front-end filtering and down-conversion. Digital sampling of the signal; perform signal preprocessing on the input Doppler radar signal; use the preprocessed data to perform N-point fast Fourier transform, and roughly calculate the frequency point; The Chirp-Z transform spectrum is refined in the above interval, and the water surface speed is calculated; the calculated water surface speed is input into the Kalman filter to smooth the speed data, thereby obtaining the surface water flow speed. The method of the invention uses the Chirp-Z transform to refine the spectrum, reduces the fence effect caused by the discrete Fourier transform, improves the accuracy of the frequency, and indirectly improves the accuracy of the speed information.

Description

technical field [0001] The invention relates to the technical field of water velocity measurement, in particular to a method for detecting surface water velocity based on Chirp-Z transformation. Background technique [0002] Hydrological monitoring activities are of great significance to the management and development of water resources. The hydrological characteristics of rivers include water level, velocity, discharge, flood season, ice age, sediment concentration, etc. Among them, the measurement of water flow velocity is an important part of water flow calculation and monitoring. Traditional contact measuring instruments are not only time-consuming to install, but also very difficult to maintain. Therefore, the demand for non-contact measuring methods is increasing, and its research and application are becoming more and more extensive. At present, non-contact measurement is usually carried out by ultrasonic, laser, radar and other methods. Among them, the radar curren...

AI Technical Summary

Problems solved by technology

[0005] (1) The noise in the echo will affect the discrete Fourier transform effect, and the velocity information is easily overwhelmed by the noise at low speed and low frequency;

[0006] (2) The defects of the discrete Fourier transform itself will reduce the accuracy of the speed calculation results;

[0007] (3) Certain disturbances in the environment are sufficient to cause anomalies in echo data, and traditional digital signal processing methods are difficult to deal with these abnormal disturbances

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