Research On Radar-based Snow Thickness Detection Method Of Ground Area

Snow is a very common factor in nature,When there is more snowfall,the area of snow cover is usually large,which will have a huge impact on local weather,transportation,agriculture and forestry.For instance,when heavy snowfall occurs on highways and other places,there will be a lot of negative impacts on traffic,which will lead to traffic jams and even traffic accidents.So there requires some snow depth detection instruments for real-time monitoring to help to take timely measures to avoid traffic accidents.At the same time,the measurement of snow thickness is also one of the most basic items in meteorology,and it has great significance in meteorological disaster warning and professional meteorological applications.There have been some studies on the use of electromagnetic waves in foreign countries to detect the depth of snow cover,and they are expected to be applied to meteorological industries and avalanche disaster warning,but at present,there are no research reports in this area.Therefore,according to the requirements of snow depth automatic observation specification,a wireless,non-contact and automatic snow depth detection method based on FMCW radar is proposed.And research the principle of high-precision ranging of LFMCW radar.A high-precision detection algorithm combining frequency method and phase method is applied to the snow thickness detection,and design a LFMCW snow detection radar hardware experimental platform.Regarding radar ranging algorithm,domestically,FFT or Chirp-z algorithms are often used to directly estimate the frequency of the beat signal so as to obtain distance data,however,its accuracy cannot meet the requirements of this paper.In addition,the research on high precision phase radar ranging has already begun in foreign countries and a series of achievements have been made.In this paper,we found that the algorithm combining the frequency method and the phase method can obtain higher ranging accuracy,which makes the radar have sub-millimeter distance resolution and is suitable for the snow thickness detection system.In order to speed up the development of the hardware experiment platform for snow depth detection radar,the RF uses ADI's ADF4159 to generate a linear modulation voltage to drive the VCO,and uses the HFSS software to design a K-band horn antenna for transmitting and receiving signals.The echo signal is downconverted by the ADF5904 module and outputs the IF signal.The IF signal is sampled by the ADC to obtain the digital signal,which is then sent to the FPGA digital signal processor for processing.The Xilinx ZYNQ7000 series development board is used,which has rich logic resources and expands performance.Because the ground snow depth detection need radar has high range performance.First,this paper proposes the oblique snow depth detection method,and analyzes and discusses the effect of distance blur on the detection performance.At the same time,the FFT ranging method and the frequency and phase combination of radar ranging algorithm are discussed.The feasibility of the algorithm in snow depth detection is verified by Matlab.The accuracy of the two algorithms is analyzed and compared,and the results show that the frequency combined with phase algorithm can further improve the accuracy of ranging based on the FFT frequency method,In the ideal case,the accuracy is less than 1mm.Secondly,it summarizes the implementation of radar ranging algorithm in FPGA and simulation in Modelsim,and compares the actual FPGA signal processing results with the simulation results of Matlab.At last,some of the hardware circuits are tested,which lays a foundation for the construction and research of radar system in the next stage of this project.