The European Geostationary Navigation Overlay Service (EGNOS) is a type of wide area differential GPS. It is a Satellite Based
Augmentation System (SBAS) being developed by European Space Agency to provide users of GPS and GLONASS (also
forthcoming Galileo) with corrected signals. It improves the accuracy of the GPS and GLONASS signals to about 1 to 2 meters.
Though nearly all the monitoring stations are based in Europe, the satellites that broadcast corrected signals also cover Africa and
Middle East. Thus, the corrected signals are receivable in Saudi Arabia but the accuracy of the signals might be degraded. Apart
from accuracy, the availability of the signals is also expected to be reduced to less than 70%.
This study assessed the corrected signal being received in Saudi Arabia by using handheld GPS (Trimble GeoXH 2005) with GPS
software (Trimble GPS Controller 2.3 and ArcPad 7). The data was collected in four Saudi cities – Jeddah, Khobar, Madinah and
Yanbu. This was to examine the possibility of using EGNOS for mobile GIS data collection and applications such as facilities/asset
management, cadastre mapping and disaster management. The results indicate that EGNOS correction improved the accuracy of
the signals by about 5m and there are variations from one city to the other. The drawbacks were availability and precision. So, it
cannot be used for time-critical projects unless the availability and precision are improved.