THE BEHAVIOUR OF GPS, GALILEO AND COMBINED GPS/GALILEO IN DIFFERENT-LATITUDE

Aswan-Faculty of Engineering-South Valley University-EGYPT

Global Navigation Satellite Systems (GNSS) have an endless number of applications in industry,

science, military, transportation and recreation & sports. Two systems are currently in operation

namely GPS (the USA Global Positioning System) and GLONASS (the Russian GLObal

NAvigation Satellite System), and a third is planned, the European satellite navigation system

GALILEO. The potential performance improvements achievable through combining these

systems could be significant and expectations are high. Computer software can be used to

simulate the overall process of GNSS (signal transmission and reception) and produce realistic

simulated GNSS measurements. Using such simulated measurements, current and future GNSS

systems and possible new applications of GNSS can be investigated. The simulated Galileo and

combined GPS/Galileo data could be generated using GNSS data simulation software. The

behaviour of the GPS, future-Galileo and combined GPS/Galileo systems are discussed in the

paper through comparing the number of visible satellites for three different latitude stations in

high, medium and near-equatorial geographical regions.