论秩亏自由网平差的性质及稳健基准的意义

On the Properties of Rank-Deficient Free Network Adjustment and the Significance of the Robust Datum

本文对秩亏自由网平差性质的分析,是基于选取原基准下的位置信息作为初值,旨在使之进一步满足测量定位的需要。本文指出,由秩亏法求得的待估参数的最优无偏估值,并非是原基准下的改正数,而内精度则可用作不受起始数据位置影响、描述整体相对位置精度的一种度量方式。以欧州参考坐标系的GPS联测计划以及周期观测的监测网为例,说明只有在满足“较好初值”的条件下才能获得所需基准下的改正数。

In this paper the characteristics of rank-deficient free network adjustment are evaluated, paying particular attention to the initial values, which are chosen as the positioning information in the original Datum. It must be pointed out, that the solution from this adjustment is not the absolute correction in this original datum, but the best unbiased estimate value for the estimated parameter. Only if the better initial value is adopted, then the corrected coordinates are with respect to this original datum. This is shown by quoting the ITRF-89-GPS-Campaign and monitoring network as two examples.