中文摘要：

观测有效性和病态性的分析与度量是改进参数估计方法、提高参数估计质量的前提条件．在GPS定位中，观测历元之间的关系优劣是观测有效性的表现特征之一．从不同角度详细地论证和分析基于正交投影算子度量观测历元之间关系的方法，将观测历元关系的度量方法应用到GPS观测的实践中，得到了很好的效果，为GPS观测等测绘实践中病态性分析及参数估计提供了较好的分析工具．

英文摘要：

Analyzing and measuring of observation effectiveness or ill-condition are me preconditions for improving the method and the quality of parameter estimation. In GPS, the relationship between observation epochs is one of the characteristics of observation effectiveness. In this paper, the method for measuring the relation between observation subspaces is demonstrated and analysed in particular, and a good result is got by applying this method to GPS surveying, which provides a better analysis tool for ill-condition or parameter estimation in surveying and mapping.