DGNSS NETWORK IN BULGARIA: STATUS AND FURTHER DEVELOPMENT

stations built either on the case-by-case basis, or as a permanent DGNSS network. With two operational and one planned beacons, the territory of the country would eventually be successfully covered east of the 24°E meridian, leaving its western regions partially or totally blank. An additional beacon (e.g. in Sofia or near-by) could be a good opportunity for the mountainous south-western area but would make no use for the remaining territory to north, where signals transmitted by foreign DGNSS stations is more likely to be expected. ABBREVIATIONS USED

DGNSS, DGPS –Differential GNSS/GPS EGNOS - European Geostationary Navigation Overlay Service GNSS - Global Navigation Satellite System GPS –Global Positioning System MSK –Minimum Shift Keying RIMS - Ranging and Integrity Monitoring Station RTK –Real Time Kinematic SBAS –Satellite Based Augmentation Systems SNR –Signal-to-Noise Ratio WAAS –Wide Area Augmentation System REFERENCES Minchev M., B. Dimitrov. GPS networks for positioning and navigation: Status and future development. National military university, Scientific conference 2002, proceedings, part III, Shumen, 2003, pp 11-19 Minchev M., A. Andreev. On the differential GPS applications. National military university, Scientific conference 2002, proceedings, part III, Shumen, 2003, pp 199-204 Roberts G., A.Grant, D.Last. Radiobeacon DGNSS coverage planning –A national case study. MTS 0-933957-28-9