【作者】 王丽英；

【导师】 宋伟东； 刘正军；

【作者基本信息】 辽宁工程技术大学 ， 地图制图学与地理信息工程， 2011， 博士

【摘要】 作为一种全新的数据获取手段,机载激光雷达(Light Detection And Ranging,LiDAR)系统的精度一直是各方关注的焦点。能否将其成果作为基础测绘产品直接应用,这是开展机载LiDAR大规模工程化应用必须面对的问题。系统误差是影响机载LiDAR系统精度的主要因素,如何消除或削弱系统误差影响,提高空间数据获取精度是机载LiDAR数据处理领域的研究热点和技术前沿,具有重要理论意义和工程实用价值。本文系统地归纳总结了机载LiDAR系统数据处理的相关理论,重点研究机载LiDAR数据中系统误差处理方法,以航带平差方法为理论核心,提出了基于航带平差的机载LiDAR系统误差处理新方法,并通过实验进行了验证,有效提高了LiDAR系统精度。全文主要研究内容如下:①机载LiDAR数据系统误差源理论分析与估计。机载LiDAR系统集成了多个子系统,其定位精度会受到来自姿态、测距、GPS定位、系统集成等多种误差的影响。这些子系统对激光脚点的定位结果的影响一般表现为系统性的,会在不同程度上歪曲定位结果。为了获取高精度的三维地表信息,就必须研究这些误差的大小和影响规律,并采取一定的措施来减小这些误差的影响。本文从机载LiDAR系统几何定位方程出发、基于误差传播规律推导了机载LiDAR系统的综合误差计算公式,分别研究了姿态角、GPS、激光测距、扫描角等多种误差源对激光脚点定位精度的影响规律,从理论上分析了机载LiDAR系统定位精度;进而全面总结和回顾了现有的系统误差消除方法。②机载LiDAR航带平差理论基础。包括机载LiDAR数据的表面表达方式、对航带平差有特殊影响的典型数据特点、航带平差的基本数学模型、主要的航带平差处理工作。在此基础上提出了完整的航带平差流程,对航带平差中涉及到的关键问题进行了研究并给出了解决方案。③提出了基于无控制三维表面最小高程差(Least Z-Difference,LZD)和最小法向距离(Least Normal Distance,LND)两种匹配算法,有效消除机载LiDAR点云数据航带间的系统误差。实验表明:使用LND和LZD两种方式进行机载LiDAR航带平差获取的结果均可以满足工程生产的精度需求;与商业软件TerraMatch的结果相比,LZD的精度和TerraMatch的精度相当,且两种方式在TerraMatch软件平差失败时也能成功的完成航带平差任务。④首次将高斯-马尔柯夫模型引入到基于无控制三维表面匹配的机载LiDAR航带平差方法中。实验表明,在对高斯-马尔科夫模型进行合理的参数配置后,能够显著提高平差的精度。⑤将传统摄影测量中的航带法区域网平差原理扩展到机载LiDAR点云数据处理中,提出了机载LiDAR航带区域网平差方法,可有效降低逐航带平差导致的误差累积。更多还原

【Abstract】 As a new means of data acquisition, accuracy of airborne LiDAR(Light Detection And Ranging) system has been the focus of attention. Whether the results can be applied directly to basic surveying and mapping products is a question we must answer when carrying out large-scale airborne LiDAR engineering application. While systematic errors are the main factors of affecting the accuracy of airborne LiDAR system, elimination of systematic error has been a key issue affecting and constraining the development and application of airborne LiDAR. Therefore, to attain high-accuracy airborne LiDAR data, it is of great theoretic and practical value to research the key techniques and methods of the elimination of systematic errors.This paper takes the strip adjustment as the key technique and main research content. The related theory, techniques and methods of airborne LiDAR data’s systematic error processing are studied to an extent. Facing to the advanced theories of airborne LiDAR strip adjustment, grasping the status and trends of technological development, according to characteristics of LiDAR data, combining of theoretical analysis, the method design, algorithm implementation, new strip adjustment methods are proposed and fulfilled. The main content and research issues of this thesis are listed as following.①Analyze the error sources and their influences on the airborne LiDAR data qualitively and quantitively. Airborne LiDAR system integrates multiple subsystems, its positioning accuracy will be influenced by INS, ranging, GPS positioning, system integration and other errors. Impact of these subsystems on the results of laser footprint positioning will usually render a systemic, distorted position results in varying degrees. In order to achieve three dimensional surface information of high precision, we have to study size and influence of those errors’, and to take certain measures to reduce the effect of these errors. From the position equation of airborne LiDAR system, this paper analyses the error propagation of LiDAR system. The errors such as the INS, GPS positioning, ranging, laser scan angle are discussed detailedly, the influenced rule of those errors are deeply studied. The academic positon precision are discuss and the stimulant numerical value of LiDAR system are deduced by the precision of its composite.②Study the LiDAR strip adjustment theory. LiDAR strip adjustment’s performance potential as well as limitations several aspects should be considered, including surface representation, error characteristics of LiDAR, surface comparisons, modeling, and adjustment techniques. So our paper reviews these fundamentals of the underlying theory, and then the most important techniques of LiDAR strip adjustment are discussed. on this basis makes a complete strip adjustment process; the key issues involved in the study are given solution.③Propose Least Z-Difference(LZD) and Least Normal Distance(LND) two matching algorithms based on 3D surface matching without control points. Effectively eliminate airborne LiDAR point cloud data systematic errors between strips. Experimental results show that: the accuracy of airborne LiDAR strip adjustment based on LND and LZD can both meet the project accuracy requirements; compared to commercial software TerraMatch, LZD and TerraMatch accuracy are at the same level, and the proposed algorithm can successfully complete the task of strip adjustment when TerraMatch software failure.④Introduce the Gauss-Markoff model to the three-dimensional surface matching based on uncontrolled airborne LiDAR strip adjustment method for the first time.Experimental results show that after reasonable parameters configuration of the Gauss-Markoff model, improved strip adjustment method can significantly improve the adjustment accuracy.⑤extend traditional photogrammetric strip block adjustment principle to airborne LiDAR point cloud data processing, propose a airborne LiDAR strips block adjustment method which can effectively reduce the strip adjustment caused by error accumulation .更多还原