Title: A self-adaptive correction method with eliminating the influence of angular response for multi-beam acoustic intensity data

Author(s): YANG Bin; HE Linbang; QIU Zhenge;

Affiliation(s): College of Marine Sciences, Shanghai Ocean University; Key Laboratory of Space Active Opto-Electronics Technology, CAS, Shanghai Institute of Technical Physics, Chinese Academy of Sciences；

Abstract: The multibeam backscatter strength (BS) is greatly affected by acoustic scattering mechanism among the process of multibeam acoustic data acquisition, which is the so-called angular response(AR). While, the AR effect has not been weakened by the acoustic hardware perfectly. There isn’t a post-processing method to correct the BS on the complex seabed sediment correctly, especially in the high-incident-angle domain. An improved self-adaptive angular response correction model for the multibeam backscatter strength data was proposed. Firstly, the mean of the BS for continuous pings data at each resample angle was calculated to obtain the AR curve. Secondly, the AR model correction parameters were extracted by means of the second derivative approach on the fitting AR curve generated from the mean BS data curve using gauss fitting method. Finally, the BS segment processing correction model for a single Ping was present, which takes the high-incidence-angle domain into account. The experimental results indicated that the mean deviation among entire transmitting section was decreased by about 30% compared with the traditional model. Especially, in the high-incidence domain, the mean deviation reduced by nearly 40% compared with traditional model, the standard deviation reduced by approximately 30% as well. The proposed method not only can weaken the influence of scattering mechanism, but also it can avoid these troubles such as BS inhomogeneity, abnormal correction in the central domain which suffered from the AR effect. Therefore, the reliability of multibeam backscatter strength is improved, and what is more, it can present the actual geomorphology of the seabed as much as possible.