An algorithm for averaging part of GNSS measurements information obtained at different times and belonging to the same baseline is given. The averaging extends to the increments of such lines’ coordinates and the accompanying covariance matrix of the increments. It is implemented using the algorithm of the classic parametric version of data LS-optimization. The design matrix of the measured increasing is built with positive single blocks size 3×3; their total number is equal to that of the baseline observation sessions. Solving the system of relevant normal equations through the method of conversion, size 3×3, gives the vector of average increments of the base line coordinates. The reverse matrix of its normal equation ratios is an averaged covariance one of average increments (system roots). Processing observational materials is carried out in the Excel electronic computational table using a synthesized version of the parametric one of the data LS-optimization, taking into account the errors of the reference points’ coordinates. The two-way processing-determined coordinates and their RMSE (root mean square error) were identical both before and after averaging.