Waveform Design And Detection Performance Analysis For Incoherent Scatter Radar

The ionosphere is an important component of the earth atmosphere, its influence on the electromagnetic wave is closely related to the human activities. Incoherent Scattering Radar(ISR) is one of the most effective method to detect the ionosphere, and it can get many kinds of parameters of the ionosphere. Due to the special nature of ionosphere target, Incoherent Scatter Radar usually probes the ionosphere with complex encoding mode and signal processing method. Based on the independently construction and test verification of the chinese first Incoherent Scatter Radar, waveform designs and detection performance analysis for Incoherent Scatter Radar are intensively studied in this paper, the corresponding experimental techniques provided for further improving the detection performance of the Incoherent Scatter Radar and promoting the research on ionospheric characteristics in china.Firstly, the evaluation method for Incoherent Scatter Radar is discussed, several important resolution are studied. the ambiguity function is studied, with the lag profile matrix, the algorithm for the autocorrelation function and the power spectrum of the scattered signal are given. The long pulse code, the Baker codes and the two-phase alternating codes are intensively studied. The advantages and disadvantages of the three coding types are comparatively analyzed with their range ambiguity functions.Secondly, the hybrid codes for Incoherent Scatter Radar and the corresponding detection performance analysis are mainly studied. The modulation mode for the Baker-coded multipulse codes, the Baker-coded two-phase alternation codes and the two-phase alternating-coded multipulse codes are illustrated in detail. The signal processing methods of the three hybrid codes are given with their range ambiguity functions.Finally, a new codes called polyphase alternating coded by Orthogonal Frequency Division Multiplexing(OFDM) is studied. Due to the disadvantages of the two-phase alternating codes, polyphase alternating codes is studied and the corresponding range ambiguity function is analyzed. According to the shortcomings of the alternating code, polyphase alternating codes coded by OFDM is proposed. Mainly modulating the multi-group codes of polyphase alternating codes to the orthogonal subcarriers of OFDM and stacking into a group; The scatter signal from each subcarriers can be got according to the orthogonality of subcarrier.