S. V. Chapligin - Student, Moscow Aviation Institute (National Research University). E-mail: kraite@mail.ru
D. P. Nikitin - Ph.D. (Eng.), Senior Lecturer, Moscow Aviation Institute (National Research University). E-mail: nikitindmitriy@mail.ru

At present time, a more extended number of application requiring the use of receivers of global navigation satellite systems (GNSS). In this situation, satellite navigation is growing rapidly: deploying new global navigation systems, on orbit deriving additional navigation space crafts, applying new signals and positioning modes. One of the most perspective paths of development of satellite navigation is the use of real-time high-precision absolute positioning mode (Precise Point Positioning - PPP). PPP mode allows you to provide positioning accuracy of about 10 cm, after a period of convergence, but for operation in PPP mode, it-s necessary to have high-precision ephemeris-time information in the user receiver. This article describes the principles of operation of PPP mode in real time, and most of the factors that have a significant impact on the positioning accuracy of the consumer receiver. The paper paid some attention to the process of formation and transmission to the user in real-time high-precision ephemeris and time information, that necessary for the operation in PPP mode. Also article provide details of some sources of precise ephemeris and time, such as the German Space Operations Center (DLR) and the Russian information - Analysis Centre (IAC), comparison of its data (supported GNSS, formation time and the accuracy its data, etc.). In the experimental part, article shows the results for precision of navigation solution in PPP mode in the real time with high precision ephemeris and time data. Showed the period of convergence research results of the navigation solution, depending on the accurate of the primary position selected as the initialization position. Was shown that the more precise primary initialize position of the receiver we know, and then the PPP solution faster reaches a steady state. Also in the paper showing results of research of accuracy when working in PPP mode, receiver used different constellations in navigation solution: only GNSS GPS, only GLONASS, and when GPS+GLONASS. These results are illustrated in the form of comparative graphs and tables. Concludes of the article describes possibility of using PPP mode in real time, techniques to reduce the period of convergence and the benefits of using PPP mode compared to the differential modes of navigation.