中文摘要：

由于自由网平差模型秩亏，法方程存在无穷多组解。从测量角度来看，就是网的绝对位置无法确定，网形浮动。为了解决这一问题，引入了基准（参考系）来固定测量网。也就是说，给定基准条件的同时也就给定了坐标系。那么基准条件中必然包含定义坐标系的信息。推导出一种法方程的通解，给出了由基准定义相应坐标系的相关公式，通过算例验证了基准和坐标系之间的关系。

英文摘要：

Because the free net adjustment model is rank-defect, the normal equation derived with the KS method has an infinite number of solutions. Geodetically, the configuration of geodetic network can not be fixed. In order to obtain a unique configuration of geodetic network, some datum conditions should be introduced into. In other words, coordinate system will be determined if datum is given. Therefore datum must involve some informa- tion for defining coordinate system. Three kinds of datum conditions and a general solution in free geodetic network adjustment are presented here, and a formula about the relation between datum condition and coordinate system is test through an example.