| With the development of IT-based warfare,the battlefield environment is increasingly complex.In order to improve the radar system's capability of detection,resolution and recognition in complex electromagnetic environment,the software defined radio technology is used in the research of radar system,and a radar experimental system is designed in this paper.All kinds of parameters of the radar experimental system are controlled by software,and can be adjusted in time to adapt to different operational conditions,which makes the radar system software,programmable and upgraded.Firstly,this paper analyzes the radar experimental system based on software defined radio.We select the physical fitness and signal mode of the radar system,and analyze the relationship between echo signal to noise ratio and working bandwidth and the relationship between the maximum detectable velocity and the maximum detectable distance,and describe the effect of window processing on the signal power and range resolution,and calculate the various losses of the radar system.Secondly,this paper designs the common radar baseband transmit waveforms and builds the radar system modeling and simulation platform.Based on the frequency modulation and phase modulation,we design the linear frequency modulation waveform,the nonlinear frequency modulation waveform,the Costas waveform,the Barker coding waveform and the multi-phase coding waveform,and analyze the performance of various waveforms,such as the peak side-lobe ratio,the Rayleigh resolution and the range resolution.At the same time,we set up a radar system modeling and simulation platform,and finish the target simulation and echo simulation,and realize the matching filter,pulse accumulation,MTI processing,Doppler processing and CFAR threshold detection and other radar signal processing algorithms.In addition,the display and control interface of the radar system modeling and simulation platform is introduced.Then,based on the software defined radio platform NI PXIe-5644 R,this paper design a software defined radio radar experiment system.We introduce the performance parameters of the software defined radio platform NI PXIe-5644 R,and propose the basic architecture of the radar experimental system based on software defined radio.At the same time,we design the host computer and the lower computer program of the RF transmitter and RF receiver,the timing control of the system and the signal processing and data processing,and analyze the data type,data storage and data flow of the radar experiment system.Finally,this paper tests,calibrates and verifies the software defined radio radar experiment system.We test the transmitting channel,the receiving channel and the signal processing module,and calibrate the system time and signal amplitude,which eliminates the system delay and the DC component and improves the accuracy of the system,and carry out the target detection experiments so that the radar experiment system can realize the target detection. |
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