GNSS are a combination of systems with different datum, satellite signals and orbit constellation in each system. The position solution of GLONASS in GPS datum causes biases. In this paper, the results of adjusting permanent GNSS network were used over separate 57 days in 2014. The results in case of using GPS only were compared to those in case of using GLONASS only in GPS datum. It is of great interest to use both GPS and GLONASS measurements in such a process, but it is required that any reference system discrepancies are corrected when the broadcast navigation information of each system is used. The biases of the two cases were compared to estimate new correction parameters between navigation systems. These parameters were developed to improve the performance of GLONASS results. The new model and two other classic models were assessed using permanent and local GNSS network in Egypt. The new correction parameters achieved the best performance with biases of 3mm. However, without using these parameters the biases reached to 15mm.