Research On The Key Technologies In Data Link System

Data link system is the most important application of information technology in military communication. Especially the Link-16 data link,which can effectively connect the operation platforms of different troops,therefore, building a highly efficient operational network and increasing the overall combat effectiveness of troops. JTIDS is the communication carrier of Link-16 data link, integrated with command and control communications, navigation, and IFF functions. The system employs a variety of coding and spread spectrum technologies to ensure its anti-interference ability, and the high-speed frequency hopping technology is the most important one.The author participated in the work of developing a fh system based on Link-16 data link system, mainly responsible for the design of the frequency hopping patten and and the synchronization algorithm, and implementing on FPGA platform. In addition, the author also studied the DOA estimation technology of smart antenna, implementing high-precision algorimth under the environment of strong coupling with URA. This work lays a foundation for the smart antenna to increase the anti-interference ability of the data link system in the future.The thesis briefly gives an introduction of the background, pointing out its significance for national defense. The thesis analyzes the system structure and characteristics and studies the main coding and spread spectrum technology of Link-16, pointing out that the high speed broadband frequency hopping technology is the most important reason that Link-16 data link has a strong anti-interference ability.Second, the thesis researchs on the the most critical technology in the frequency hopping and designs the FH pattern and synchronization algorithm. With the help of m sequence, L-G model and wide interval processing method, the thesis successfully designs high-performance wide interval frequency hopping pattern. A new FH pattern synchoronization method combining the precise clock synchronization,waiting search synchronization and synchronization-head method is proposed. In terms of frame synchronization, the thesis implements a synchronization method based on digital correlation of eight channels.Finally, the thesis studies the prospect of smart antenna technology in future data link system to increase its anti-interference ability.Emphasizing on the DOA estimation, two algorithms based on URA to realize high precision estimation under the environment of strong coupling are proposed, and the simulations are given to verify the effectiveness.