The Study On Frequency-hopping Communication Techniques Used In Network-Torpedo

Network-torpedo is a new informationization torpedo, which can realize identifications in real time, pursuit and attack on target with information obtained effectively from the nets in the battlefield at any time. it is one of an important trends to develop the torpedo technology. Acoustic communication technique could provide a reliable communication between the network-torpedo and the nets, and is a crucial technology in realizing network-torpedo communication. According to the current research status and the characteristic of network-torpedo communication, a deep study which includes FH/MFSK, Error correct coding and synchronization is carried out by theoretic research, computer simulation and experiment on the lake. The main research contents in this dissertation are as follows:(1)The characteristics of the network-torpedo`s UWA(Underwater Acoustic) channel is carried out by theoretic research and computer simulation, and a UWA channel model, which concludes the time-varying fading, multipath interference and AWGN(Additive Gaussian White Noise), is established and simulated.(2)According to the characteristics of network-torpedo`s UWA, The communication is confirmed to use the Frequency-Hopping technique by contrast with different aspects. Based on the research of the principle of the FH, the parameters selection, and the mathematical model of the FH system, a UWA frequency-hopping communication system using noncoherent FSK modulation is designed and simulated by using the UWA channel model, which is suit for network-torpedo communication.(3) Three ECC (Error correct coding) schemes: RS code, convolutional code and serial concatenated code that include the technique of interleave are proposed. The performance of the ECC schemes is simulated by using the model of underwater acoustic frequency-hopping communication system , and the results under the different cases are given and compared.(4)The different synchronization methods are studied. A method of synchronization with correlated detection is designed and implemented by comparing the various capture programmes.(5)According to the underwater acoustic frequency-hopping communication system, an experimentation is performed in anechoic water tank and on the lake, and the experimental dates are analyzed, the results shows: this kind of communication system can effectively suppress the multipath interference and has a high reliability in long distance. Compared with the other relative research results., the system has some superiorities in an error correction capability in complex time variant multi-path and fluctuation of shallow water acoustic communication channels. And it is suitable for using under the circumstance of the network-torpedo communication.