Approximate estimations of variance components in an adjustment computation

Abstract

An alternative expression has been derived for the variance factors when estimating weights according to the Iterated Almost Unbiased Estimation (IAUE) technique. The variance factors are expressed in terms of the redundancy numbers of the observed quantities. A variance factor can also be approximately estimated by finding the ratio of the redundancy numbers at any two successive interations. The numerical example of the first‐order leveling network of Taiwan indicates: that stabilization of the redundancy number of an observation occurs as the variance factor associated with it converges to unity; and that for those variance factors which fail to converge, the redundancy numbers of the corresponding observations tend to decrease monotonically as the iteration proceeds.

Key words:

• MINQUE
• AUE
• redundancy number