# 2019_programme: THE ALGORITHM OF THE UNDERWATER ACOUSTIC SOURCE COORDINATES DETERMINATION USING THE CORRELATION FUNCTION OF THE SIGNAL

**Session:**04. Towards Automatic Target Recognition. Detection, Classification and Modelling**Organiser(s)****:**Groen Johannes, Jans Wolfgang, Pailhas Yan, Myers Vincent**Lecture****:**THE ALGORITHM OF THE UNDERWATER ACOUSTIC SOURCE COORDINATES DETERMINATION USING THE CORRELATION FUNCTION OF THE SIGNAL

**Paper ID:**786

**Author(s)****:**Mashoshin Andrei**Presenter:**Mashoshin Andrei**Presentation type:**oral**Abstract:**One of the actual practical problems of underwater acoustic is to determine the coordinates of the underwater sound source (SS) in the passive mode. In many cases the determination of SS coordinates equals the determination of its class.\nA large number of methods and algorithms are proposed to solve this problem. One of these methods is based on the use of the correlation function (CF) of the broadband multipath signal received by sonar to determine the range and depth of the SS. Information about the range and depth of the SS in the CF contains in the location on the time axis of narrow-band peaks due to interference of correlated source signals that came to the antenna on different rays. Each pair of such signals corresponds in CF to one interference maximum (IM) with an abscissa equal to the difference in the propagation times of these signals.\nDetermination of the coordinates of the SS using the information contained in the CF, is to search for each IM, detected in the CF, a pair of theoretical signal rays, which would satisfy two conditions:\n1) the amplitude of the IM in KF due to interference of these rays should exceed some threshold;\n2) the value of their propagation times delay should be as close as possible to the abscissa of the IM.\nThe investigation has shown that in many practical cases the described method leads to unacceptably large errors. This is due to two factors:\n1) low accuracy of theoretical rays parameters calculation due to bad knowledge of hydroacoustic conditions in the region of work, as well as due to their random fluctuations;\n2) objective ambiguity of this method.\nThe aim of the work is to synthesize an algorithm of the underwater source of broadband acoustic signal coordinates determination, taking into account these 2 factors.\nAccounting of the 1st factor is achieved by:\n control of measurement and calculation errors of rays parameters;\n averaging of estimates of the coordinates obtained at relatively long time intervals.\nConsideration of the 2nd factor is achieved by narrowing the area in which the source coordinates are found with the use of other less accurate methods of the SS coordinates determination.\nThe work presents the synthesis of the algorithm and the results of its simu-lation, which showed that in the deep sea at sufficiently large distances, the developed algorithm potentially provides a high-precision SS coordinates. In the shallow water, as well as at short distances in the deep sea, the estimates of the coordinates using the developed algorithm gives the ambiguity in the SS coordinates.\n

**Corresponding author:**Prof Mashoshin Andrei

**Affiliation:**Concern CSRI Elektropribor,JSC

**Country:**Russian Federation

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