Global Navigation Satellite Systems Capabilities and Opportunities

摘要

The capabilities of the current global navigation satellite system (GNSS), namely, the U.S. Global Positioning System (GPS), are first reviewed and the error sources affecting system performance are briefly described. Selected advances made recently to improve its accuracy, reliability, and availability are discussed and illustrated with examples. These include real-time kinematic (RTK) positioning, integration with self-contained inertial navigation systems (INS), attitude determination, and "indoor GPS". The latter, which deals with signal availability using weak signals, has resulted in intense research and development activities. It has also launched a rapid expansion of location-based services (LBS), a market expected to grow to over US $25B worldwide annually by the end of the decade. The characteristics and advantages of the second generation GPS, namely GPS II, that will become available throughout the decade ahead are summarized. Finally, the major characteristics and impact of Galileo, the European Union's GNSS, also to be deployed this decade, are discussed. The major conclusion s that GNSS multiplicity and performance improvements will have a major impact on the user community.