Research On Doppler Velocity Signal Processing Method And Design Implementation Of Train Speed Measurement System

With the popularity of high-speed trains in recent years,high-precision train speed measuring devices have become more and more important.The traditional contact speed measurement method is directly installed on the train wheel-set.Due to the slip or idling of the wheel,the accuracy of the speed measurement is low and the reliability is poor.In response to the shortcomings of the traditional contact speed measurement method,the non-contact Doppler velocity measurement method is becoming more and more important.Doppler speed measurement method is installed at the bottom of the train.According to the Doppler effect,the vehicle speed is obtained by detecting the transmitted wave and the echo difference frequency signal.This method has high speed measurement accuracy,strong real-time performance and high reliability.This paper mainly completes the research on the key technology of train Doppler speed measurement system and the design and implementation of the speed measurement system.The main research contents include:Firstly,the method and principle of non-contact Doppler velocity measurement are studied.The characteristics of Doppler velocity measurement signal with continuous wave as the transmitted wave are analyzed,and the correspondence between Doppler frequency and train speed is found.At the same time,the basic method of train Doppler speed measurement is studied.Secondly,research on the processing algorithm of Doppler velocimetry signal.Firstly,the typical algorithms in classical and modern spectral estimation are studied,and the representative algorithm of Doppler frequency extraction is mainly studied.At the same time,the anomalous phenomenon of Doppler velocimetry signal is analyzed,and two improved algorithms based on Burg method are studied.And the FIR filtering of the Doppler velocimetry signal is realized.Then,the speed measurement error standard of high-speed train is analyzed,and the parameter selection method applied to Doppler speed measurement signal is studied.Finally,aiming at the high precision and real-time characteristics of the train speed measurement system,a variable parameter speed measurement method based on model parameter selection is proposed.The simulation results show that this variable parameter velocity measurement method can meet the high precision and real-time requirements of train speed measurement.Thirdly,the frame structure of the train speed measurement system is studied,including the modular design of the system and the working mode of the system.The TI TMS320F28335 was selected as the signal processor to complete the construction of the prototype of the speed measuring system.For the hardware design of the speed measurement system,the design and implementation of the RF module,the DSP signal processing module and the key hardware circuits are completed.Complete the design and development of the speed measurement software,and use the C language in the CCS development environment.Finally,the train speed measurement system is tested.Firstly,the Doppler echo is simulated by the signal generator to test the speed measurement system.Then,using the indoor rotating rail equipment to simulate the low-speed running state of the train and launching the real continuous wave signal through the IVS167 radio frequency block to complete the indoor experimental verification of the speed measuring system.The test results verify the correctness of the speed measurement system at all stages of signal processing and the applicability of the system over the entire speed range of the train.The train Doppler speed measurement system designed in this paper has achieved the advantages of high precision,real-time and stability of high-speed trains,which laid a solid foundation for the development of domestic Doppler speed measurement.