多波束测深条带拼接区误差处理方法研究

发布时间：2018-08-18 13:22

【摘要】：条带拼接区测深数据的质量控制是多波束数据处理的重要内容,对提高多波束测深精度和获取整体区域真实海底地形具有重要意义。本文对多波束条带拼接区测深数据误差削弱方法进行了较为系统和全面的研究分析。内容涵盖:测深点的归算理论推导及分布特征的分析、海底地形的最优空间构建方法的选择、测深误差影响分类及相应的处理手段、基于中位参数的多面函数抗差估计自动滤波测深异常值的研究、以及地形频谱分析的系统性残余误差削弱方法研究等。论文的主要内容概括如下:⑴推导了海底波束脚印点的归位计算过程,从而获得准确的测深点坐标。将获得的测深点大地坐标转换为空间直角坐标,以避免后期以经纬度为坐标数据处理时产生扭曲变形大的问题。此外,分析在不同的信号发射模式下,等角和等距波束的分布特征。⑵根据所得的测深点空间直角坐标,采用各类空间内插方法来构建海底地形,根据时间损耗、DEM可视化效果以及残余误差各项评估值等指标综合选取最优的内插方法。实例表明:实际应用过程中,海底地形DEM的构建要综合测区海底地形复杂程度和测深点分布特征来选取自身最优方法。⑶对多波束测深误差的影响从不同的层面进行分类,并根据测量过程中各类型误差是否共同作用深度值,分析了声速剖面测量和姿态测量误差对条带拼接的影响。此外,阐述了误差性质类型中异常值和系统误差的研究方法,为后续本文处理方法的提出提供指引方向。⑷针对多项式曲面拟合进行测深滤波不彻底且逼近真实的海底地形能力有限,以及将最小二乘求得的残余误差作为抗差初始值严重干扰抗差性能等问题,本文提出了基于中位参数的多面函数抗差估计法来自动滤波测深异常值。该方法在多面函数已知节点的选取上进行了改进,结合角度-弦高联合准则和点的离散度进行抽稀处理,此外,综合了多元参数的中位参数具有很强抗差能力的特性。实验结果表明:该方法能最大限度和最大效率上提取区域的特征点,DEM效果图中可以看出基本没有异常突出的起伏点,同时又保证海底地形连续变化的特征。⑸尽管一些系统性测深误差在数据处理中有所改正,但多波束测深系统自身测量误差及其诱导性的残余误差依然存在,严重影响测深的精度,导致条带拼接区出现哭笑脸现象。因此,本文提出基于地形频谱分析的方法来削弱系统性残余误差的影响,并与DFT方法进行对比分析。实验结果表明:采用分区多条带分割处理,通过适当的稀释多面函数中已知节点的间隔,合理地降低拟合精度来达到快速处理整个测区系统性残余误差削弱的目的。相比DFT方法的处理,地形频谱分析法所处理后的测深数据残余误差的削弱影响得到了显著的提升。
[Abstract]:The quality control of bathymetric data in strip splicing area is an important part of multi-beam data processing. It is of great significance to improve the accuracy of multi-beam bathymetry and to obtain the real seabed topography in the whole area. In this paper, a systematic and comprehensive analysis is made on the method of weakening the sounding data error in the multi-beam band splicing area. The contents include: the derivation of the theory of bathymetric points and the analysis of the distribution characteristics, the selection of the optimal space construction method of the submarine topography, the classification of the influence of sounding errors and the corresponding processing methods, The study of the outliers of multi-plane function robust estimation based on median parameters and the method of systematic residual error weakening in topographic spectrum analysis are also presented in this paper. The main contents of this paper are summarized as follows: 1 deduces the calculation process of the underwater beam footprint point and obtains the accurate bathymetric point coordinates. The geodetic coordinates of the bathymetric points obtained are converted into the spatial rectangular coordinates to avoid the problem of large distortion when the data are processed with latitude and longitude coordinates. In addition, the distribution characteristics of isometric and isometric beams in different signal transmission modes are analyzed. 2. According to the rectangular coordinates of bathymetric points, various spatial interpolation methods are used to construct submarine topography. The optimal interpolation method is selected synthetically according to the visualization effect of time loss Dem and the evaluation value of residual error. The example shows that in the practical application process, the construction of submarine terrain DEM should be based on the complex degree of submarine topography and the distribution characteristics of bathymetric points to select its own optimal method .3 to classify the effect of multi-beam sounding error from different aspects. According to the depth value of different types of errors in the measurement process, the influence of the errors of sound velocity profile measurement and attitude measurement on strip splicing is analyzed. In addition, the research methods of outliers and systematic errors in the nature of errors are described. To provide guidance for the following methods in this paper. 4. The depth filtering for polynomial curved surface fitting is incomplete and the ability to approach the real submarine terrain is limited. Taking the residual error obtained by the least squares as the initial value of robust and seriously disturbing the robust performance, this paper presents a multi-plane function robust estimation method based on median parameters to automatically filter the sounding outliers. This method is improved in the selection of known nodes of multi-plane function, and is thinned by combining the joint angle-chord height criterion and the dispersion of the points. In addition, the characteristics of strong robust ability of the median parameters of the multivariate parameters are synthesized. The experimental results show that the method can extract the feature points of the region to the maximum extent and the maximum efficiency. It can be seen from the Dem effect diagram that there are basically no prominent fluctuation points. At the same time, it ensures that the characteristics of continuous variation of submarine topography. 5. Although some systematic sounding errors have been corrected in data processing, the residual errors of the multi-beam bathymetric system itself and their induced errors still exist, The precision of sounding is seriously affected, which leads to the phenomenon of crying and smiling face in the splicing zone. Therefore, a method based on topographic spectrum analysis is proposed to reduce the influence of systematic residual error and is compared with DFT method. The experimental results show that the system residual error of the whole survey area can be quickly processed by using partition multi-band segmentation and by properly diluting the interval between the known nodes in the multi-plane function and reasonably reducing the fitting accuracy. Compared with the DFT method, the residual error of the bathymetric data processed by the topographic spectrum analysis method is greatly improved.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P207.1

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