Research On Intrusion Detection Method Of Railway Foreign Objects Based On Radio Frequency Sensing

With the rapid expansion of Chinese railway,there are also hidden dangers of foreign objects invading the track at any time.The track foreign objects intrusion detection based on radio frequency sensing method has attracted wide attention due to its characteristics of flexible deployment,low cost and high detection accuracy.In this paper,according to the demand of general speed train and high speed train,the intrusion detection scheme based on channel state information and frequency-modulated continuous wave is proposed by the theory of spatial spectrum estimation,and the intrusion detection and high-precision positioning of track foreign objects are realized.The target is classified and recognized by extracting RCS data.The main research contents and innovations of this paper are as follows:(1)Based on the commercial network card of WiFi,the foreign object intrusion detection function in the environment of general speed train is realized on the basis of the existing communication.The principle and process of super-resolution AOA estimation using CSI data based on MUSIC algorithm is analyzed.The influence of the change of signal coherence on CSI data in the process of two foreign object invasion is studied.An adaptive CSI spatial smoothing based on foreign object invasion state is proposed.(2)In order to eliminate the static clutter signal interference caused by trackside equipment and environmental factors in the process of foreign object invasion,a static clutter suppression algorithm based on MUSIC pseudospectral is proposed.The change of the upper spectral peak of MUSIC pseudospectrum in the process of foreign object intrusion is analyzed,and the characteristic that the pseudospectrum of static clutter signals on each packet is basically unchanged is studied.A static clutter suppression algorithm based on cross grouping is proposed to improve the anti-interference performance of intrusion detection.(3)Based on frequency modulated continuous wave,a high-precision positioning method combining FMCW radar and MUSIC algorithm is proposed,and the intrusion detection is realized by using RCS,so as to meet the high requirements in the environment of high-speed train.This paper introduces the 2D-RDM high precision range and velocity measurement method of FMCW radar,the construction of space matrix of radar received signal and the process of super-resolution AOA estimation.In order to realize the classification and recognition of foreign bodies,the Swerling model based on phase analysis and composite target RCS data simulation were proposed based on the analysis of simple structure RCS modeling.The wavelet transform is used to preprocess RCS data and achieve fine-grained classification of RCS.