Hydroacoustic system with complex signals for communication and positioning of underwater vehicles
Abstract
Hydroacoustic system with complex signals for communication and positioning of underwater vehicles
Incoming article date: 12.02.2019The method of local positioning of underwater vehicles by hydroacoustic system with linearly-frequency-modulated probing signals is considered. The method is based on measuring the range to the object and calculating the angles of arrival of echo signals on two or more spaced antennas. To increase energy and noise immunity signals with linear frequency modulation (LFM) are used. The scheme of towing an underwater vehicle with an acoustic beacon and the location of a hydroacoustic interferometer with two receiving antennas on a towing vessel are presented. The possibility of practical use of this method for high-precision measurement of the spatial position of an underwater towed or Autonomous vehicle relative to a surface vessel and, accordingly, the possibility of geographical reference of acoustic images and sea-bottom profilograms obtained by an underwater vehicle is experimentally shown. The results of full-scale tests of the experimental positioning system for its testing in the coastal zone of a small pond are presented. The block diagram of the local positioning equipment is presented. Examples of experimental distributions of the power module of echoes over the range are given for correlation processing of the acoustic beacon LFM signals. The paper also proposes the use of narrow-band traverse broadband parametric systems for communication between Autonomous unmanned underwater vehicles (ANPA) moving "in a flock". Describes the main specifications of the system and the experimentally measured in hydroacoustic basin of the directivity pattern of the antenna at the average rate of pumping and difference frequencies. The features of signal propagation in shallow sea are presented.
Keywords: hydroacoustic systems, side-view interferometric sonar, local positioning systems, parametric antenna, data transmission system, broadband antenna