Dfh Automatic Link Establishment And Its Synchronization Technology

Differential Frequency-Hopping(DFH) Communication, also called Correlated Frequency-Hopping Communication, is a new type of communication technique which is well developped in recent several years. Compared with the Traditional Frequency-Hopping Communication technique, DFH possesses the advantages of high hopping-rate, wide transmission band and simple hardware structure etc. Moreover it shows outstanding superiorities in anti-interference and anti-fading abilities.First, this paper made analysises and contrasts in characterizations between Traditional Frequency-Hopping Communication and Differential Frequency-Hopping (DFH) Communication, made initial design and trial in applying technique of Automatic Link Establishment to DFH system and brought up a basic model.After that, this paper improved the acquisition methods of Differential Frequency-Hopping system through using soft decision, multiple correlations of frequency-hopping pattern and the combination of these two methods, which boosts 4~5dB of the acquisition performance, and this paper strengthens the anti-interference abilities hugely through using acquisition method with self-adaptation threshold.In the end, this paper used multi-hop signal energy (track depth) to calculate time bias estimation, improved about 5dB of tracking performance, analyzed the relationship between tracking performance and track depth, and realized good tracking performance in low signal-to-noise condition.