The Estimator or Mean Square Error of Unit Weight Considering the Influence of Initial Datum Error

In this paper,the formulae for calculating the estimator of mean square error of unit weight—— б₀ have been derived in the adjustment of observation equations with condition equations and the adjustment of condition equations with unknowns considering the influence of initial datum error.Then,this paper gives two examples which exp-lain that the influence of initial datum error on б₀ must be considered.