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.