Research On The Design And Processing Of Coding Frequency Modulated CW Proximity Detection Signal

In the continued development of science and technology,radio range technology has been greatly developed,military and civil aspects of the close-range target accurate ranging and anti-interference ability also has a higher demand.As a typical proximity detection signal,pseudo-code frequency modulation signal has good characteristics and wide application prospects.However,the traditional pseudo-code frequency modulation technology has some limitations,such as low ranging accuracy,the use of manual threshold method,weak anti-interference ability and so on.This thesis designs a pseudo-code frequency modulation ranging system based on K-cell CFAR algorithm for automatic threshold detection,and improves and optimizes the ranging accuracy and anti-interference ability of the system.The main contents of this thesis are as follows:(1)This thesis introduces the traditional pseudo-code frequency modulation signal processing technology,and establishes the corresponding Simulink simulation system through mathematical theory derivation.It provides a reliable basis for further research on improving ranging accuracy and anti-interference performance.(2)To improve and optimize the problem of manual threshold setting in the traditional pseudo-code frequency modulation and distance system,K-cell CFAR algorithm is combined with the traditional pseudo-code frequency modulation and distance technology to optimize the relevant processing methods of the distance part.Various parts of the pseudo-code FM signal simulation system based on K-cell CFAR algorithm were built,and the simulation ranging results of the traditional manual detection threshold method and the improved K-cell CFAR automatic detection threshold algorithm were compared and analyzed.The results show that the latter realizes the threshold detection automation on the basis of maintaining the ranging accuracy of the system.The anti-interference performance of the system is improved.This part also provides a theoretical basis for further improvement of ranging accuracy and anti-interference performance.(3)Aiming at the influence of burr error on range accuracy caused by demodulation of pseudo-code frequency modulation system under various noises,Deglitch processing technology is adopted to burr filter split code demodulated from echo signal.A Deglitch signal processing simulation module is designed,and the simulation results show that this method has a good burr filtering effect.This part of the simulation module is combined with the pseudo-code frequency modulation and spacing system to Deglitch the split code under the noise interference of the signal-to-noise ratio.The simulation results show that compared with the traditional spacing method,Deglitch processing technology can still perform the spacing more accurately under the condition of a small signal-to-noise ratio.(4)Aiming at the problem of spectral dispersion interference caused by the pseudo-code frequency modulation system in the process of signal transmission,a twin waveform signal is designed to suppress spectral dispersion interference.The traditional twin waveform signal is analyzed,and the twin waveform is designed for the pseudo-random code frequency modulation signal.By designing the time-frequency shift modulation signal,the difference between the twin waveform and the original waveform is simulated and compared,the suppression of spectral dispersion interference is realized,and the anti-interference performance and reliability of the system are improved.