Research On Design And Application Of A MIMO High Frequency Surface Wave Radar Waveform

High frequency surface wave radar is a kind of new system radar,which has important strategic significance in China's coastal defense construction.As "21st century radar",high frequecny surface wave radar can cover tens of thousands of square kilometers of ocean area round-the-clock,which can effectively improve China's real-time monitoring capabilities of territorial sea and airspace,and enhance China's national defense strength.However,the huge footprint of the high frequecny antenna array,seriously affects the flexibility of the radar system and hinders the application of high frequency surface wave radar.Therefore,the miniaturization of high frequency surface wave radar can effectively solve the problem of space limitation,and it is very important for the popularization and application of high frequency surface wave radar.MIMO radar can utilize waveform diversity technology to effectively improve the utilization of time and space,which expands the effective aperture of radar system,and has great potential in solving the miniaturization problem of high frequency ground wave radar.Based on the background of high-frequency ground wave radar,this thesis studies the MIMO orthogonal waveform design method suitable for practical engineering applications,and analyzes some common problems in practical engineering applications,and verifies the practical usability of the waveform.Firstly,this thesis proposes a hybrid coding waveform design method,called improved discrete frequency phase encoding waveform(IDFPCW),combining frequency encoding and phase encoding to improve the degree of freedom of waveform design.The ambiguity function and the corss-ambiguity function,combined with the background of the high-frequency ground wave radar are derived and analyzed.Combined with the background of high frequency surface wave radar,the waveform was simulated and the spectral characteristics and doppler characteristics of the waveform were analyzed.Then,in order to find the optimal coding sequence,the parameters of IDFPCW are optimized by non-dominated sorting genetic algorithm(NSGA).The optimization results are compared with the previous design waveforms,and the multi-objective optimization characteristics of NSGA are used to analyze the relationship between target functions.The mutual restriction relationship between them gives the parameter selection strategy in the actual engineering environment.Finally,the limitations and actual performance of IDFPCW inthe actual radar system is analysed.The actual target detection experiment is carried out by modifying the actual radar system to verify the practicality of the IDFPCW waveform.The results show that the IDFPCW waveform has good orthogonal characteristics,especially the autocorrelation sidelobe level peak is significantly reduced,and it has good multi-target detection capability.Through the semi-physical experiment simulation experiment and the actual system target detection experiment,the correctness of the theoretical analysis and conclusions in this thesis is verified.