.fh / Ds Hybrid Spread Spectrum Communication System And Its Anti-jamming Measures Modeling And Simulation

As a new communication mode, the spread spectrum communications are widely used in military communications,satellite communications,mobile communications and C 3I (Command, Control, Communications & Intelligence) system, because of its well multiaddress access, low probability intercept, the excellent performance of anti-interference and secrecy. So the study of a hybrid direct sequence frequency hopping(DS/FH) communication system and the techniques to reject the interference is very important in communication field.In this dissertation, a hybrid FH/DS system and its interference rejection and anti-jamming technologies are studied. The main work includes two parts: The study of the key technologies in a hybrid FH/DS system and the modeling and simulation of a hybrid FH/DS spread spectrum communication system; the design and simulation of interference rejection mode in a hybrid FH/DS system.In the first part the technique of PN sequence synchronization and carrier synchronization in digital receiver for hybrid FH/DS spread spectrum communication system are studied. The dissertation analyses its mathematical model and design of parameters, and finish its simulative model in simulink. Through the experiment, the dissertation testifies that the mathematical model is correct and simulative result can approximately reflect the performance of real system. The main work of this part is listed as following:(1) For PN sequence acquisition scheme, the dissertation studies the all digital matched filters acquisition scheme and its mathematical model and parameters, and designs simulative model for acquisition loop. Then the dissertation compares the theoretical analysis of the detection probability on white noise and its computer simulation result, and testifies validity of the simulative model.(2) The dissertation studies a noncoherent all digital delay lock loop suited for chip timing synchronization and costas loop for carrier recovery, analyses their mathematical model and parameters respectively, and designs simulative model for tracking loop. Then the dissertation compares the theoretical analysis and the computer simulation result, testifies validity of the simulative model.In the second part the dissertation designs several interference suppression technologies for FH/DS spread spectrum communication system. Through the experiment, the dissertation studies different interference suppression technologies'performance. The main work of this part is listed as following:(1) Design the algorithm used in determining and suppressing the narrowband interference, and the anti-jamming simulative model. Through the experiment, the dissertation testifies validity of the interference suppression algorithm.(2) Design the algorithm used in determining and suppressing the broadband linear FM interference, and the anti-jamming simulative model. Through the experiment, the dissertation testifies validity of the interference suppression algorithm.