北京54坐标系坐标转换的探讨

Discussion on coordinate trasformation for Beijing geodetic coordinate system 54

坐标系之间的相互转换常用相似变换法,但如果公共点存在较大的误差,计算结果会使转换模型存在较大的差异.结合原有北京54坐标系和由GPS成果换算得的54坐标系之间进行相互转换的实例,探讨了公共点的误差对转换模型的影响,提出了转换计算前应对公共点进行筛选的设想,并利用Baarda数据探测法原理,对公共点进行筛选,剔除偏差较大的公共点,有效消除了公共点间隙较大的缺陷,使转换后的坐标更加符合相似变换的特征.

The coordinate systems are often transformed under the similarity transformation rule. The problem is, when a significant error between two public points exists, the calculated result will cause a large gap between transformed models. This paper analyzed the example of the transformation between the original Beijing geodetic coordinate system 54 and a new geodetic coordinate system 54 based on GPS data. Then it was discussed that the public point coordinates＇ error could affect the transformed models. The proposal is that public point coordinates should be selectd before calculating. In order to eliminate the gaps between the public points and transformed coordinates, how to use Bacrda Data Snooping theory to select public point coordinates was discussed. This method seems to be an effective way to eliminate the defect of the relative large gaps between public point coordinates and to make the transformed coordinates more coincident with similarity transfomation feature.