Satellite-Based Navigation Systems

This chapter focuses on various satellite-based navigation systems. The most well-known and widespread system currently used for localization of a radio-receiving terminal is the global positioning system (GPS). All GPS satellites share the same frequency bands, making use of the code division multiple access (CDMA) technique. The transmitted signal on each sub-band is a low-rate binary phase shift keying (BPSK) digital signal containing the so-called navigation (NAV) data that are used by the receiver to perform ranging. Galileo is the European Global navigation satellite systems (GNSSs) providing a global positioning service under civilian control. It has to be interoperable with GPS and GLONASS, the American and Russian GNSSs, respectively. Like GPS and Galileo, GLONASS is based on several ground stations that monitor and control the satellites and their signals. The GPS and Galileo stations are spread on the globe, to guarantee a better control of the constellation and its signals. Differential GPS (DGPS) is an enhancement to GPS that uses a network of fixed, ground-based reference stations to broadcast the difference between the position of a receiver located at each station, as derived instant by instant using the GNSS, and the known fixed positions of the stations themselves. © 2012 Elsevier Ltd All rights reserved.