部分公共点高程有异常时空间直角坐标与地方坐标的转换

Transformation of rectangular coordinates and local coordinates under the condition of some common points with height anomaly

在求空间转换模型的七参数时,有些公共点高程数据精度不高但平面坐标精度高,这些公共点常常不能被采用,无疑浪费公共点的平面信息。本文提出一种改进模型,利用公共点的平面坐标和正常高信息与其空间直角坐标建立转换关系。高斯坐标对空间坐标的导数关系很难解析出数学模型,但利用数值方法可确定其转换关系。通过算例的比较,得出当某些公共点的高程有异常时,对求得的七参数是有影响的,而去除这些点的高程信息后求解七参数,转换检验点得到的结果与参考值一致,从而证明该剔除模型的正确性。

When solving the seven parameters of spatial transformation model,some common points with low height accuracy but high plane accuracy cannot often be used,which undoubtedly is a waste of the plane information of these common points.The paper proposes a model which uses the plane coordinates and normal height information of common points to establish their transformation relationship with the space rectangular coordinates.It is difficult to resolve the mathematical model through the derivative relationship between the Gaussian coordinate and space coordinate,but the numerical method can be used to detennine the transformation relation.Through the comparison of calculation examples,it is concluded that the solution of seven transformation parameters will be affected when some common points with height anomaly,and the conversion result of the test points will be consistent with the reference values after those anomalies are deleted,which also verifies the validity of the model.