The objective of the doctoral thesis was to acquire scientific research results on GNSS reference system performance in static and dynamic measurements, the communication channel load, develop solution to expand the area of coverage of EUPOS®-RIGA and reduce maintenance costs and to substantiate it with results from theoretical and practical research. Main tasks of the thesis: theoretical research of maximum accuracy of GNSS measurements and necessary conditions; develop the method for taking and processing the measurements for dynamic mode, which would provide reliable results; carry out accuracy studies in static and dynamic modes of measurements; develop the solution to improve the EUPOS®-RIGA reference system; study the necessary capacity of the communication channels between user and reference system server and between the base stations and server of the reference system. Topicality of the thesis is represented by still growing use of GNSS reference systems in specific branches. Nowadays GNSS reference systems are used more widely and precise geodetic surveying is not the only economic sector where they are used. GNSS reference systems are used, e.g. in control of automatic road construction machines or agricultural machinery. To control machines, the measurements have to be done in dynamic mode and such measurements do not have reliable research history till now. Chapter four is dedicated to the measurements in dynamic mode. Chapter one and chapter two are dedicated to research of standard GNSS accuracy in absence of the reference systems, as well as benefits from reference system use and how studies and descriptions of the advanced accuracy is achieved by using the carrier phase of the GNSS signals. Chapter three depicts the results of measurements in static mode. To correctly estimate the accuracy in static mode, several sessions of measurements was long term research activity (2007–2014). Calculations were made without measurement attraction to the classic geodetic networks. In such a way obtained results demonstrate the repeatability and mutual trust. In chapter four the author of this paper proposed and described original method how to take and process the measurements in dynamic mode. Beginning of the chapter contains information on the results of simple measurements. In further text the author of this paper describes the innovative method to process the measurements. It allows to rate the accuracy of the measurements more precise than before. General idea of the method is to provide the reference value which is used to estimate the accuracy of measurements of position determination. Final chapter is dedicated to research of the load of communication channels. Author have calculated theoretical data stream between the server of reference system and user basing on RTCM standards. These results are compared with actual data streams logged onto server. The results can be used by the users to choose an appropriate capacity of data channel and mobile data license fee. Data flow between user and server is defined by a RTCM standard but there is no such a standard for data flow between base station and server and amount of transferred data depends mainly on number of satellites in view and standards of the hardware producer. As a result of these studies author of this paper can offer opportunity to reduce costs from system maintenance by choosing an appropriate data channel subscription.