Research Of The Incoherent Scatter Radar Waveform Detection Technology

The ionosphere is the partially ionized plasma region above the Earth, where is from fifty or sixty kilometers to one or two thousand kilometers, it is also the important part of the Sun-Earth space environment. The researching ionosphere has an important significance for the military, communications, agriculture, etc. The incoherent scatter radar(ISR) is one of many efficient tools, which can detect lots of space plasma parameters, such as electron density, ion temperature, electric ion temperature ratio. Because of small scattering cross-sectional area, the echo signal is so weak. In order to extract the ionosphere parameters effectively and attain statistical accuracy, ISRs need to use lots of most complicated coding.In ISR, signal processing is one of key technologies. Actually, the echo signal autocorrelation needs to be amended by ambiguity function. However, if the condition and height of detection were not same, coding and receive filter response would be different, then the ambiguity function may also be different. It is the problem for us to research ambiguity function, especially, simulation and comparison of the two dimensional ambiguity function. In addition, how different codes affect the power spectrum of the actual echo signal, which is a problem to be solved in space exploration. In this paper, we analyzed the ambiguity function and the signal processing mixed with noise and clutter of barker code, long pulse code and alternating code. The introduction of main aspects as follows:First, we introduce the history, the current research status and significant of ISR, here we mainly introduce the ISR of China, including the basic principle of the ISR, Fourier transform, Wiener-Khinchin theorem, Frequency mixing principle, Thomson scattering from a signal electron, Scattering from density fluctuations, Measurement principle and signal processing.Second, we research basic formula of ambiguity function and derivation of them, the history, the generation and the basic properties of three ordinary waveforms(barker code, long pulse code and alternating code).Third, we research the pictures of amplitude ambiguity function, range amplitude ambiguity function, range ambiguity function, two-dimensional ambiguity function and delay ambiguity function of single pulse code, barker code, long pulse code and alternating code. Besides, we analyze the advantages and the disadvantages of the above three ordinary waveforms.Finally, we simulate the actual exploring experiment of ISR and research waveform processing simulation mixed with noise and clutter of barker code, long pulse code and alternating code.