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中文核心期刊

一种消除角度响应影响的多波束声强数据自适应改正方法

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

  • 摘要: 针对多波束反向散射强度(Backscatter Strength,BS)数据在采集过程中受到声学散射机理而产生的角度响应(Angular Response,AR)影响,而目前声学硬件方面尚未完美解决且现有后处理改正方法在复杂海底底质环境下适应性较差,尤其在高入射角区域的改正效果甚为不理想的问题,为此,给出了一种基于散射强度的自适应角度响应改正模型。首先获取连续脉冲(Ping)平均散射强度数据的角度响应曲线;其次使用高斯拟合方法对角度响应曲线进行平滑拟合处理,进而对其解算二阶导数提取角度响应模型改正参数;最后给出顾及高入射角区域的单Ping反向散射强度数据的分段处理改正模型。实验结果表明,该方法与传统方法相比,整个发射扇区散射强度平均偏差精度约提高30V,尤其在影响较大的高入射角区域,平均偏差精度约提高40V,并且该区域的标准差精度也提高了近30%。该模型较好地解决了多波束在非正射情况下获取海底精准散射声强的问题,削弱了声波散射机理的影响;同时也解决了散射强度过渡不均衡、中央波束区域改正异常等问题。因此,提高了多波束反向散射强度的可靠性,可以真实地呈现出海底实际的地貌。

     

    Abstract: The multibeam Backscatter Strength(BS)is greatly affected by acoustic scattering mechanism when sampling the multibeam acoustic data,which is the so-called Angular Response(AR).While,the acoustic hardware has not weakened the AR effect perfectly,and it is unsatisfactory for published post processing methods to correct the BS on the complex seabed sediment,especially in the high-iricident-angle domain.An improved self-adaptive angular response correction model for the multibeam backscatter strength data is proposed.Firstly,the average of the BS for continuous Pings data was computed to obtain the AR curve;Secondly,the AR model correction parameters are extracted by means of the second derivative approach on the fitting AR curve generated from the previous one using gauss fitting method.Finally,the BS sectional processing correction model for a single Ping was present,which takes the high-incidence-angle domain into account.The experimental results indicated tliat the mean deviation among entire transmitting section was decreased by about 30%compared with the traditional model.Especially,in the high-incidence-angle-domain,the mean deviation reduced by nearly 40 V compare with traditional model,the standard deviation reduced by approximately 30%as well.The proposed method not only can solve the problem of obtaining the precise backscatter strength data on the seabed,which 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,what is more,it can present the actual geomorphology of the seabed.

     

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