Study On The Signal Process Technology Of Typical Pseudo-random Code Distance System

The pseudo-random code distance system works by making full use of the remarkable autocorrelation characteristics of pseudo-random code.Owing to its precise distance measurement ability and excellent anti-jamming performance,it is proved to be one of the important development directions of distance system.The Doppler effect on the process of the echo signal is reduced and the Doppler tolerance is boosted by means of the difference frequency signal generated by the pseudo-random code phase modulation combined with linear frequency modulation distance system,which determines the distance between target and the combined system by using the good autocorrelation characteristics of pseudo-random code. Therefore,it has important theoretical guiding significance for the research and application of the pseudo-random code ranging system by studying the signal processing technology of the complex system.In this paper,the relevant principle on the signal processing technology of pseudo-random code phase modulation and linear frequency modulation is introduced in detail,then,the characteristics of the pseudo-random code signal and sawtooth wave linear frequency modulation signal and their combined signal is analyzed detailedly in their time domain and frequency domain.Based on the discussion of the operating principle of pseudo-random code phase modulation and linear frequency modulation complex distance system,the related process of the transmitting signal and the echo signal of the system is deduced,and then the selection of main parameters of the combined distance system is discussed,in addition,the receiver model of the system is structured, besides,the anti-noise performance of the complex system is analyzed deeply.Finally,the bandpass filter circuit,signal source circuit of sawtooth wave linear frequency modulation,mixer circuit,amplifying and shaping circuit,digital correlator and anti-jamming circuit are designed,furthermore.These circuits are simulated by using the software Matlab,the simulation results suggest the function of signal process of the combined system is realized successfully.