Design And Implementation Of OFDM Pulse Radar Based On USRP

OFDM(Orthogonal Frequency Division Multiplexing,orthogonal frequency division multiplexing)radar has attracted much attention because of its large timebandwidth product,good anti-jamming performance,high spectrum efficiency and easy digital processing.In recent years,with the continuous enhancement of the function of digital signal processors,the research and application of radar based on software radio is very active.The combination of software radio and radar has produced many new systems and new concept radars.Software radar and OFDM radar are important directions.The OFDM radar does not use the classical LFM waveform,but uses the broadband OFDM waveform,which not only improves the spectrum efficiency,but also improves the ranging resolution.Based on the USRP RIO 2943R(Universal Software Radio Peripheral Reconfigurable I/O)platform of NI company,this paper makes full use of the highly configurable and LabVIEW powerful graphical programming functions of the platform.This paper constructs a functional configurable OFDM radar prototype,and tests and analyzes the main technical specifications of the radar.The following work has been carried out:Firstly,research on the related theory and technology of OFDM radar.On the basis of discussing the basic principle of radar,radar equation,fuzzy function,radar type,OFDM principle and so on,it analyzes the important content of OFDM radar's waveform orthogonal characteristic,peak to average ratio,system composition and so on.It provides theoretical support for the modeling and prototype realization of OFDM pulse radar.Secondly,modeling and analysis of OFDM pulse radar based on MATLAB.First,the model of OFDM pulse radar is established by combining OFDM with radar.Then,the transmission unit in the model is described.The frame format and main parameters of the OFDM waveform are described in detail.Then,the basic principle of the reception and signal processing unit is introduced,and it is proved that the signal processing method is not only suitable for single target.The detection is also suitable for multi target detection.Finally,the power spectrum estimation method based on OFDM waveform and periodic graph is used to simulate the power spectrum of the transmitted signal and the fuzzy function of the waveform,and the echo signal is analyzed.Finally,prototype implementation of OFDM pulse radar based on USRP.Based on the idea of software and hardware co development,and taking full advantage of the characteristics of USRP configurable,OFDM pulse radar prototype based on USRP and LabVIEW has been developed.First,the USRP platform is introduced,mainly including the two parts of LabVIEW and NI USRP RIO 2943 R.Next,the framework of the prototype of the OFDM pulse radar is put forward.The model and parameters of the related hardware are introduced.Then,the working procedure of the radar is introduced with the transceiver software developed in the LabVIEW environment.After that,the FPGA core chip based on USRP realized the flexible configuration of 64QAM-OFDM and 16PSK-OFDM two waveforms.Finally,the range is carried out under the scenes of three stationary targets,and the received target echo data are introduced into the MATLAB environment for processing,and the feasibility and effectiveness of the OFDM radar based on USRP are verified.