ION Technical Content
Operational Status of GNSS
| Abstract: | During the past several years, a substantial number of advances have occurred in the development of an operational Global Navigation Satellite System (GNSS). This paper discusses the principal recent activities of the international participants, including the plans and programs of the United States, Canada, Europe, Russia and Asia to the extent they are clear at this time. The components of a GNSS are described, including the role of GPS and GLONASS, the principal elements, as well as the satellite and surface augmentations that are planned. A brief description of the current status of GPS and GLONASS is given, including the operational and performance character- istics of the current constellations. The planned GPS launches for 1996 are described for both the Block IIA and Block IIR spacecraft. The satellite augmentations addressed include the Inmarsat III satellites planned for use with the Wide Area Augmentation System (WAAS), the European Geostationary Navigation Overlay System (EGNOS), Japan’s MT Sat, and a variety of other geostationary orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) satellite systems that are planned primarily for communication, but which in nearly all cases also incorporate navigation functions. The surface augmentations include the USCG marine beacon DGPS data link system, the FM radio sub-carrier DGPS service providers (DC1 and Accupoint), private DGNSS capabilities, the FAA Local Area Augmentation System (LAAS), and others. The current status of Selective Availability (SA) and the Anti Spoof (AS) encryption of the authorized (military) GPS signals is discussed. The activities relating to the implementation of a second civil frequency for GPS are covered including the concern relating to the possible ten year delay in using the future Block IIF spacecraft in lieu of the nearly operational IIR. GLONASS status includes the use of an antipodal re-use of frequencies in the constellation and the movement of the GLONASS L1 band occupancy down to below 16 1 OMHz and later to 1610MHz to avoid interference with the mobile satellite service (MSS) and the radio astronomy bands. The future growth and benefits associated with the GNSS are discussed, principally focussing on the growth and user applications of GPS. An estimate of the GPS receivers in current use is given with projections of the market growth anticipated through the turn of the century. An indication of the variety of applications is given, emphasizing the substantial and increasing uses in farming and construction, in automobiles and trucks, for surveying and geodesy, for synchronization and precise timing, for all phases of aviation, for military applications and for obtaining GIS position data. A brief summary of the operational status of GNSS concludes with optimistic comments and projections concerning its future. |
| Published in: |
Proceedings of the 1996 National Technical Meeting of The Institute of Navigation January 22 - 24, 1996 Loews Santa Monica Hotel Santa Monica, CA |
| Pages: | 17 - 23 |
| Cite this article: | McDonald, Keith, "Operational Status of GNSS," Proceedings of the 1996 National Technical Meeting of The Institute of Navigation, Santa Monica, CA, January 1996, pp. 17-23. |
| Full Paper: |
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