Research On Differential Frequency Hopping Communication Countermeasure

Differential Frequency Hopping (DFH) is a new type of the Spread Spectrum Communication. Different from conventional FH technique whose FH pattern is based on non-linear transformation of pseudo-random code, DFH pattern, which is built on argodic process of a directed graph, takes on a new asynchronous DFH system, with correlation introduced into the DHF sequence, such new system can be applied into tactical radio station for military use. Owing to the implementation of special FH pattern and high-speed FH, the overwhelming advantage of anti-jamming is formed. Consequently, the research on the DFH system and its jamming are of significance.The thesis describes the basic mode of the DFH communication system, analyzes the basic principles and characteristics of DFH communication with reference to general FH communication, studies some critical techniques such as frequency transfer function, signal detection and multiple access technique in DFH communication, and also makes a theoretical analysis of the anti-jamming capability of the DFH communication system. The thesis briefly summarizes the classic jamming mode of general FH, investigates preliminarily the jamming of DFH, and also puts forward the estimated jamming of G function. Through simulation, it shows that there are some methods to jam DFH system. After investigating the implementation scheme of frame synchronizing signal jamming, and puts forward jamming synchronous head and forgery end-frame, finally designs scheme of a kind of jammer.