Underwater Acoustic Channel Anti Multi-path Frequency-hopping Communication Synchronization Technology

Underwater acoushc conunnication is very twortant to nahonal defence and widelyused in ocean research and development. lt is well Anown that the multi?ath effeet resultS insignal fading and intersymbol interference (ISD, wnich causes great difficulhes inPeWces of transndssion in underwater acoushc cotnmnication. In this paPef we usedfrequency diversity method to overcome the problem of signal fading, and used thefrequency-hoPping method to ebonate the ISI caused by multi-path. Synchredzation is one ofthe key teCboques of FH conunnication, the paPer provides a synchrOndation system fOrunderwate FH coIIUnunication.The pape firstly analyZes the fondng and characterishcs of multi-path effeeL presentSseveral methods of resisting mulh-path effect. And, paPer setS forth the fundaInntals offrequency-hOPping conunnicahon and sets up a math model to explain quanhtatively thestrong power of frequency-hopping method of elindnating ISI and muIhTath. Then, the paPerintroduces some conunon synchronization acquisihon methods used in FH conunnication,analyZes and contrastS the differnce of designmntS of synchronization acquisihon in detail.On the demand of application and according to the soluhons menhoned above, a method ofdisplacement waiting autO-sy'nchronizing is put forward, which is based on match filters. At theend a comPlete and speeflc set of hardware circuitS and softWare programS which haPlementSthe scheme, is also presented in the Ancle.The synchronization system was tested in the pool and in the shallow wate nearM port, the result of the test shows that itS Performance is satisfactOry...