American Society of Civil Engineers

Estimation of Variance Components Using a Step-by-Step Approach

by Cüneyt Aydin, (Yildiz Technical Univ., Dept. of Geomatic Engineering, Geodesy Division, 34210, Esenler-Istanbul, Turkey. E-mail:;

Journal of Surveying Engineering, Vol. 137, No. 2, May 2011, pp. 40-46, (doi:

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Document type: Journal Paper
Abstract: We may obtain a unique parameter vector solution from a combination of individually estimated parameter vectors by adjusting different observation groups. This kind of combination method, the so-called step-by-step procedure, is widely used in geodesy. We derive Helmert-type variance-component estimates for several observation groups via this step-by-step approach. In the estimation step, only individual results are used; hence, this procedure is called step-by-step estimation of variance components. The novel approach is applied to a horizontal control network and a leveling network.

ASCE Subject Headings:
Geomatic surveys
Variance analysis

Author Keywords:
Variance components
Step-by-step method
Helmert-type estimates