Research offers expanded version of the relationship to improve measurement accuracy (provided by Otrenbski), which include correlated or free geodetic networks, with correlated or incorrelated observations, which are processed according to the Least Square theory. In addition to enhancing the Global accuracy, Research gives additional formula takes into consideration the enhancement of each observation (local precision). the validity of the proposed formula was proved depending on the Idempotent matrix. In addition to the general concept of the reliability of geodetic network (described in literature), Research gives the formula of the relationship between improvement of measurement accuracy and one of internal reliability features (provided by Pelzer), and used in the evaluation of geodetic measurements. Research find and gives the basic mathematical indicators of the interaction of processing model with the occurrence of errors in geodetic measurements.