UDC 621.396
THE CHOICE OF SIGNAL SEPARATION METHOD IN HYDROACOUSTIC CONTROL CHANNEL
B. I. Filippov, Ph.D. (Tech.), associate professor of NSTU, Novosibirsk; This email address is being protected from spambots. You need JavaScript enabled to view it.
One of the main issues in the development of hydroacoustic communication channels (HACC) is the choice of the ensemble of signals and the method for separating the signals of control commands between bottom stations (BS) and pop-up modules of satellite communication system (PM SCS). In principle, any of the known methods of channel separation can be used to separate the signals between hydroacoustic autonomous station (HBAS) and PM SCS: time, frequency and code (in the form of signals). The aim of this work is to justify that the signal exchange between the vessel and the bottom station is carried out by sessions and begins with the transfer of command from a ship. At HBAS there is no known time for the commencement of control command transfer from the vessel. If binary sequences are used as a start signal, address signals and commands, then a simple device consisting of a binary signal receiver can be used to receive them, the output of which includes decoders and other decoders corresponding to the received signals. The results of comparative tests of the considered digital DFM and DRPM receivers showed that they have similar characteristics of noise immunity. The use of DRPM signals provides a small, about 1,5 dB, power gain and cost savings for the implementation of equipment in comparison with the usage of DFM signals, which makes it possible to recommend the use of DRPM signals for the implementation of HACC equipment.
Key words: hydroacoustic channel, discrete modulation, methods of transmission and reception, digital receivers.