基于多尺度数学模型的波束角效应改正方法

Beam angle effect correction method based on multi-scale mathematical model

为解决复杂水域下单波束测深波束角效应引起的地形失真难题,提出了一种基于多尺度数学模型的单波束测深波束角效应改正方法。该方法基于测深换能器波束“锥形”发射的形态、水下地形三维空间形态建立波束角效应多尺度数学改正模型,利用Horn算法拟合改正模型关键尺度水下地形点空间上坡度、坡向,实现三维空间下测深波束角效应的改正。通过乌东德库区白马口-龙街河段测深试验数据进行精度验证,以机载LIDAR点云数据为基准,对试验区域改正前、后的单波束数据进行对比分析。结果表明:改正后较差主要集中在区间[-0.25m,0.25m],且分布符合测量随机误差的规律,波束角效应带来的影响明显减弱;改正后测深中误差精度提高48.6%,倾斜地形水下测量的精度得到有效提升;论证水下地形的坡度是影响波束角效应的主要因素。该方法为波束角效应的改正研究提供了新的方向,对于提高单波束测深精度具有一定的借鉴意义。

In order to solve the problem of topographic distortion caused by single beam sounding beam angle effect in complex waters,this paper proposes a single beam sounding beam angle effect correction method based on multi-scale mathematical model.This method establishes a multi-scale mathematical correction model of beam angle effect based on the morphology of the sounding-transducer beam and the three-dimensional spatial form of underwater terrain.The Horn algorithm is used to fit the slope and slope direction of key underwater points,so as to realize the correction of the sounding beam angle effect in three-dimensional space.An accuracy verification test for the depth test data of Baimakou to Longjie section in Wudongde Reservoir area was carried out,and the single beam data of the test area before and after correction were analyzed by taking the cloud data of aero LIDAR as base.The results show that the difference after the correction is mainly concentrated in the interval[-0.25 m,0.25 m],the distribution conforms to the law of random error of measurement,and the influence of beam angle effect is significantly weakened;after the correction,the mean square error of the sounding measuring is increased by 48.6%,and the accuracy of underwater survey of sloping terrain is effectively improved;it is convinced that the slope ratio of underwater terrain is the main factor affecting the beam angle effect.This method provides a new direction for the correction of beam angle effect and has some reference for improving the accuracy of single beam sounding.