| These days, Global Navigation Satellite System (GNSS) technology plays a critical role in positioning and navigation applications. Use of GNSS is becoming more of a need to the public. Therefore, much effort is needed to make the civilian part of the system more accurate, reliable and available, especially for safety-of-life purposes.;With the recent revitalization of Russian Global Navigation Satellite System (GLONASS), with a constellation of 20 satellites in February 2009 and the promise of 24 satellites by 2010, it is worthwhile to concentrate on the GLONASS system as a method of GPS augmentation to achieve more reliable and accurate navigation solutions. The use of GLONASS, in addition to GPS, provide very significant advantages such as increased satellite signal observation, and reduced horizontal and vertical dilution of precision factors. In particular, because of the limited number of GPS satellites, urban canyons and other locations with restricted visibility, such as forested areas, have problems acquiring and tracking a sufficient number of GPS signals. However, with the availability of combined GPS and GLONASS receivers, users will eventually have access to a 48-satellite constellation and the performance in these types of areas will improve accordingly. |
