| Orthogonal phase-coded signal is the key technique for radar anti-interference. The orthogonal bi-phase/four-phase coded signal optimization algorithms and the side-lobe suppression algorithm are analyzed in the thesis.Two parts are divided in the thesis. The orthogonal bi-phase coded signal optimization is analyzed for some carrier-based aircraft radar first in the thesis. Genetic algorithm, to make the peak of side-lobe, integrated side-lobe of auto-correlation and cross-correlation as low as possible, is used to search bi-phase code, then the effect of the Doppler shift for bi-phase coded signal is analyzed in detail. For orthogonal four-phase code optimization, two methods of direct way and indirect way are used to optimize them. The direct way optimizes by directly coding based on gradient genetic algorithm, and indirect way by the quantitative for phases of nonlinear frequency modulation signal,then analysis and simulateon of the above two methods are given. Meanwhile, the side-lobe suppression algorithm for bi-phase and four-phase codes is proposed, to enhance the main lobe and side-lobe ratio.The second part, combined with the practical project, realizes 16-channel digital emission array system on the platform of on-site Field Programmable Gates Array. The hardware platform is designed and to finish the program of the 16-channel synchronous digital up covert of the orthogonal coding signals. |
PDF Full Text Request