基于CGCS2000的地方独立坐标系模型构建及实例分析

发布时间：2018-06-26 05:35

本文选题：坐标转换 + 布尔莎模型　；参考：《西安科技大学》2013年硕士论文

【摘要】：随着“数字城市”项目的开展，研究各测量坐标系统的相互转换模型，可以实现全国各地测绘成果的快速转换和更新，使得原有的测绘成果低损精度地转入CGCS2000坐标系下使用，满足数字城市建设的需要；分析研究各种高程转换方法，实现高海拔地形复杂区域高程的有效转换；构建2000地方独立坐标系，在现阶段及今后的测绘工作中具有重要的理论意义和实用价值。本文以贵州省某地级市GPS控制网数据为基础，在CGCS2000椭球和地方椭球之间建立严密的数学关系，重新推导更加严密的大地坐标微分公式，优化地方椭球建立的方法，解决高海拔山区地形投影变形较大的问题，建立了基于CGCS2000的地方坐标系，满足该市地理空间框架建设的需要。论文中分析推导了坐标转换的模型误差的消除方法，，比较各种GPS高程拟合方法，探讨了大地微分公式的参数间函数关系，优化了地方坐标系构建模型，得出如下结论：（1）重心化过程消除已知点分布不均所带来的模型误差。稳健估计过程则排除了已知数据可能存在的粗差对转换精度的影响，保证小角度坐标的转换的精度；本文精化大角度七参数模型的旋转矩阵，削弱旋转参数间的相关性对求解参数的影响，通过不同角度下的模拟参数实验效果明显改善。（2）分析各种高程拟合模型的实用性，选择第三章所述的高程拟合算法，通过实例分析发现，BP神经网络模型拟合效果较好。（3）分析原大地坐标微分公式发现文献[2]和文献[8]中的大地坐标微分公式有误，对其进行改正，结合椭球参数间的函数关系，重新推导大地坐标微分公式如4.21式所示，实例比较可知改进大地坐标微分公式转换精度明显优于原大地坐标微分公式。（4）在以CGCS2000椭球为基础椭球，优化传统的地方独立坐标系构建模型，建立基于CGCS2000的地方坐标系。其长度最大变形为2厘米，精度比《城市测量规范》所规定的地方坐标系长度变形小于2.5厘米每千米要高。综合第4章地方坐标系理论模型和算例分析来看，在高海拔山区，构建地方独立坐标系选用椭球膨胀法较其他两种方法更好，投影长度误差最小，点位变化不大。在选择基准点时，取平均大地高点较其它两种选取方法更为合理。
[Abstract]:With the development of the "Digital City" project, the research on the mutual transformation model of the surveying coordinate system can realize the rapid transformation and update of the surveying and mapping achievements in various parts of the country, and make the original surveying and mapping achievements be transferred to the CGCS2000 coordinate system with low loss precision. To meet the needs of digital city construction; to analyze and study all kinds of elevation conversion methods, to realize the effective height conversion of high altitude terrain complex area; to construct 2000 local independent coordinate system, It has important theoretical significance and practical value in the present and future surveying and mapping work. Based on the data of GPS control network in a prefecture-level city of Guizhou Province, this paper establishes a strict mathematical relationship between CGCS2000 ellipsoid and local ellipsoid, rededuces the more rigorous differential formula of geodetic coordinates, and optimizes the method of establishing local ellipsoid. The local coordinate system based on CGCS2000 was established to solve the problem of large deformation of terrain projection in high elevation mountain area, which can meet the needs of the construction of the city's geo-spatial framework. In this paper, the methods of eliminating the model error of coordinate transformation are analyzed and deduced, and various GPS height fitting methods are compared. The functional relationship between the parameters of the geodetic differential formula is discussed, and the model of the local coordinate system is optimized. The conclusions are as follows: (1) the barycenter process eliminates the model errors caused by the uneven distribution of known points. The robust estimation process eliminates the influence of the gross error of the known data on the conversion accuracy and ensures the accuracy of the transformation of the small angle coordinate. In this paper, the rotation matrix of the large-angle seven-parameter model is refined. The influence of the correlation between rotation parameters on the solution parameters is weakened, and the experimental results of simulated parameters at different angles are obviously improved. (2) the practicability of various height fitting models is analyzed, and the height fitting algorithm described in Chapter 3 is selected. Through the analysis of examples, it is found that the BP neural network model fits well. (3) by analyzing the original geodetic coordinate differential formula, we find that there is an error in the geodetic coordinate differential formula in reference [2] and [8], and correct it. Combined with the function relation of ellipsoid parameters, the differential formula of geodetic coordinates is rededuced as shown in formula 4.21. The comparison of examples shows that the transformation accuracy of the improved geodetic coordinate differential formula is obviously better than that of the original geodetic coordinate differential formula. (4) based on the CGCS2000 ellipsoid, the traditional local independent coordinate system is optimized to build the model. The local coordinate system based on CGCS2000 is established. The maximum deformation of its length is 2 cm, which is higher than that of the local coordinate system of less than 2.5 cm per kilometer. In chapter 4, the theoretical model of local coordinate system and the example analysis show that the ellipsoidal expansion method is better than the other two methods in constructing local independent coordinate system in high altitude mountain area, the projection length error is minimum, and the point position is not changed much. When selecting reference points, the average ground height is more reasonable than the other two methods.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P226

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