Availability, reliability and accuracy of GPS signal in Bandar Baru Bangi for the determination of vehicle position and speed

The Global Positioning System (GPS) provides special features which can be utilized for wide range of applications. By providing information such as location, direction and speed, GPS is traditionally used for navigation. Nowadays many more applications, from farming, surveying to incident detection in fact fully utilized the GPS. This study accesses GPS signal and determines vehicle location and speed parameter such as maximum speed, maximum acceleration and deceleration. Assessing the GPS signal is important before implementing any application in certain area. The availability and reliability of the GPS are influenced by several variables, for example tall building, geometrical condition and big tree might block the GPS signal and reduce the data quality. It will affect the efficiency of any application based on GPS and become useless. Two types of tests had been setup, static positioning and mobile positioning where GPS probe vehicles were used to collect data in Bandar Baru Bangi, Malaysia trunk roads. The preliminary tests show promising results of availability and reliability percentage, accuracy, number of satellites in view and horizontal dilution of precision values. The next stage of this research apply the speed parameter obtained for automated incident detection (AID) algorithm.