New satellite navigation systems and moderenization of current systems, why and for whom?

Information about user's position can be obtained from specialized electronic position-fixing systems, in particular, Satellite Navigation Systems (SNS) as GPS and GLONASS, and Satellite Based Augmentation Systems (SBAS) as EGNOS, WAAS, MSAS. All these systems are known also as GNSS (Global Satellite Navigation System). As the number of GPS and GLONASS satellites visible by the user is sometimes in restricted area not sufficient, and these SNS cannot provide information about integrity, there is one service for civil users only etc., new systems, global as well as regional, must be constructed. The last years gave a rise to many important changes in the operational status and practical exploitation of all these systems. New SNS as Galileo in Europe and Compass (Beidou) in China, new SBAS as GAGAN in India and SDCM in Russia, new regional SNS as IRNSS in India and QZSS in Japan are actually under construction. Additionally the new satellite blocks as GPS IIF and III, and GLONASS K1 and K2, the new signals as GPS L5 and L1C, and GLONASS LC3OC and L1OC, the new services and possible applications of the future system Galileo are presented in this paper.