Analysis And Research On Signal Processing Of Incoherent Scattering Radar

The ionosphere is the most critical part of the earth's atmosphere environment.Incoherent scatter radar(ISR)is the most powerful ground-based equipment to monitoring the ionosphere.This kind of radar has many advantages,such as high resolution,long distance coverage,high precision and strong detection capability.Those echo signals are weakly scattered due to thermal fluctuations in the plasma located in the upper atmosphere.These ionospheric parameters could be derived from the scattered signals,therefore,one of the most important and critical techniques is the processing of scattered echo signals in ISR.Due to the particularity of scattering targets,and therefore,ISR must use complex coding schemes,and it is necessary to correct the scattering signal by the ambiguity function.Therefore in the present study the four codes were simulated based on the theory of ambiguity functions firstly.Secondly,this paper performs parameter inversion of AMISR data based on data processing software package.The main tasks are as follows:First,the research status of ISR at home and abroad and the development of signal processing are introduced.Based on the principle of incoherent detection,the relationship between the scattering spectrum and the autocorrelation function(Acf)of the echo signal is researched,which provides a theoretical basis for the subsequent parameter inversion.The theory of the ambiguity function is mainly studies,then the relationship between the echo signal Acf and the ambiguity function are introduced.Second,in this paper,long pulse code,Barker code,alternating code and composite code are simulated using the theory of the two-dimensional ambiguity function(TDAF)and the range ambiguity function(RAF).A simulation comparison of different coded autocorrelation functions(Acf)and power spectra was performed.It provides the basis for the subsequent deblurring of different codes.In addition,by comparing and analyzing the advantages and disadvantages of various waveform coding,it provides a better basis for the actual detection of waveform selection.Third,researching the method on echo signal power spectrum to extract ionospheric parameters.In this paper,using the measured data processing software package of the complete ISR simulation system,the parameters of the AMISR measured data are inverted and compared with the IRI model to verify its correctness.