Broadband noise signal source positioning method using flat linear antenna in Fresnel zone near ‘water-air’ boundary

Abstract

Ways of broadband noise signal reception using flat linear extended antenna in Fresnel zone near surface boundary enabling to determine direction, range to the source and depth of its immersion simultaneously with detection are considered. The effect emerging when signal source and receiver are located near «water-air» interface and two beams arrive from source to receiver (direct beam and beam reflected from the surface) is investigated. The supervisor of compensation of delays of signal arriving to M receivers of the antenna focuses receiving system in the point of the expected positioning of the source. In case of dual-beam signal it may result in emergence of two range focusing points in space. It is shown that focal spots may have high range spreading or practically merge depending on the relative positioning of the source and the receiver. Method of source submergence depth analysis at known ranges to two focal spots is offered for the first case. Method of consolidated signal processing which includes additional scanning of time delays in possible delays of signal between beams with uniform delay for all antenna elements is offered for the case when focal spots are not separated. It is demonstrated that when obtaining maximum signal power entered delay will be functionally connected with depth of immersion of the source that enables carrying out joint determining of direction, ranges and depths of submergence of the source in offered method. Moreover, it is demonstrated that method of consolidated processing enables to increase power of arriving signal up to 50 % in the point of maximum response as compared to conventional signal reception algorithm using flat linear antenna in Fresnel zone.