Many Received Signal Strength (RSS)-based fingerprinting positioning techniques have been recently proposed to exploit the increased coverage and availability of WiFi access points (AP) in both indoor and outdoor environments. One practical challenge in the fingerprinting approach is on the device diversity problem and several prior works have attempted to mitigate this adverse effect. However, these existing algorithms can only work well for indoor environments. In this paper, we propose a novel power-gap elimination (PGE) algorithm for outdoor vehicle positioning. Our experimental results show that the fingerprinting-based vehicle positioning is also feasible even in the presence of device diversity, which can be
handled by incorporating the PGE. Moreover, we also propose a new method to obtain the level of accuracy for a location estimate in a real-time manner, so that a location estimate can be more informative.