Present satellite radio navigation systems, their performance and user receiver concepts

The contribution gives an overview of present and future navigation systems and their augmentations as GPS, GLONASS, GALILEO, WAAS, EGNOS, MSAT, QZSS, BEIDOU, GAGAN. Performance of systems depends on technical parameters and we will try to evaluate it and to present our opinion on advantages of them for different applications and in various situations (reception of week signals suffering from great attenuation under vegetation canopy, in urban canyons, influence of reflections and multipath). The last part of contribution deals an application of software radio technology for user receiver design and results obtained from experiments with different algorithms of processing of satellite navigation systems signals.