Global Navigation Satellite Systems: A Survey

Global navigation satellite systems (GNSS), involving satellites, ground reference station infrastructure and user equipment to determine positions anywhere on earth, have revolutionized the mapping, surveying and tracking industry. These systems allow small electronic devices to determine their location (longitude, latitude and altitude) in within a few meters using time signals transmitted along a line of sight from orbiting satellites. The past decade has seen tremendous growth in the use of these systems across many areas of the society. Among the currently used GNSS, the global positioning system (GPS) from the USA is the only fully operational satellite navigation system. Russia also operates its GNSS called GLONASS, which will become fully operational by 2010. Fueling growth in the coming decade, several next generation GNSS (Galileo, GLONASS, Enhanced GPS etc) are currently being developed. In this paper we present a survey of what technological improvements will these next generation GNSS incorporate in order to deliver better accuracy, reliability and availability to the spatial information industry