WiFi GPS based combined positioning algorithm

If nowadays, positioning becomes more and more accurate, and covers better and better a territory (indoor and outdoor), it remains territories where traditional (and basic) positioning system (GPS, gsm or WiFi) and hybrid ones (GPS- gsm, GPS-WiFi, GPS-WiFi-gsm, …) are insufficient and requires research investment treating combined positioning. In this paper we propose a GPS-WiFi combined positioning algorithm, based on trilateration technique. Real experiments and other simulation are conduced and demonstrate accuracy gains, even where various criteria dilution of precision (GPS dop's criteria, or ours WiFi geometrical and signal attenuation's dop proposal, or hybrid dop one's) indicate all the disruption of positioning service. A testbed scenario issued from a real urban campus environment validates not only our GPS-WiFi combined positioning algorithm but also an implementation of pertinent positioning techniques and dop's criteria. This work constitutes a further step to better position everywhere and to ensure continuity of a positioning service.