V.V. Dvorkin, S.N. Karutin, P.B. Glukhov

Global navigation satellite systems (GNSS) development creates new areas of practical applicationof user equipment, which require higher accuracy of navigation and timing service. Precise positioning applications use differential navigation methods, relative positioning and wide area differential correction. Last principle is used in WAAS (US), EGNOS (EC) and currently created national system for differential correction and monitoring (SDCM). There are several events during last years, which built serious basement for the further GNSS positioning accuracy improvement. GLONASS and GPS passed a deep modernization and there are new generations of navigation satellites on orbit, international GNSS service (IGS) made huge studies for developing navigation satellites ephemeris and clocks precise determination algorithms, allowing to estimate these parameters with an accuracy of few centimeters. These circumstances allow developing precise point positioning algorithms for navigation by using navigation signals of GPS and GLONASS with an accuracy equal to relative positioning methods. There is SDCM hardware and software complex making precise ephemeris and clocks for GNSS satellites, which is a core of precise point positioning algorithms. There is a set of experiments with SDCM reference stations showing that it is possible to obtain GLONASS/GPS ephemeris and clocks with an accuracy below 15 cm, and make precise positioning with an accuracy of few centimeters with no difference on type of GNSS constellation. These results show that SDCM could be used as a base for developing real time precise positioning system.