中文摘要：

介绍了评价法方程系数矩阵病态性常用的条件数指标的基本原理，分析了用条件数评价平差系统病态性的不足，并将其归结为3类风险。指出了重新参数化是利用条件数评价病态性的必要前提，并论述了重新参数化改善由数值计算引起的病态问题和避免条件数评价的范数风险，成功地解释了航空摄影后方交会时解算结果的稳定性和条件数指标的矛盾。

英文摘要：

We discuss the principle of condition numbers that used for evaluating the extent of ill-posed problem of normal matrix. There is a contradiction between the stability of solution and the condition number of resection in photogrammetry. We find that it is not suitable in all cases to evaluate the extent of ill-posed problem by condition numbers. Three types of possible risks for evaluation of ill-condition extent with condition numbers were addressed in detail. Removing of outliers and re-parameterization are the prerequisites for evaluation of ill condition extent with condition numbers. There are two effects of re-parameterization for ill- posed problems. One is improving the problem of ill-condition caused by numerical computa- tion, and the other is avoiding the risk of using norm to evaluate the extent of ill-condition. Results of simulated experiments show that the proposed approach is validate for improving the problem of ill-condition.