Improvement of GPS and Glonass positioning accuracy by multipath mitigation using omnidirectional infrared camera

This paper describes a precision positioning technique that can be applied to vehicles or mobile robots in urban or leafy environments. The availability of satellite positioning is currently expected to improve due to the presence of positioning satellites such as US GPS, Russia's Glonass and Europe's Galileo. Due to the serious multipath impact on positioning accuracy in urban or leafy areas, however, improvements in satellite positioning availability do not necessarily facilitate highprecision positioning. Our proposed technique mitigates the GPS and Glonass multipath using an omnidirectional infrared (IR) camera that can eliminate the need for invisible satellites using IR images. With an IR camera, the sky appears distinctively dark. This facilitates the detection of the borderline between the sky and surrounding buildings and foliage due to the difference in atmospheric transmittance between visible light and IR rays, since buildings and foliage appear white. The proposed technique can automatically and robustly mitigate the GPS and Glonass multipath by excluding invisible satellites. Positioning was evaluated with visible satellites, which have less multipath error and without using invisible satellites. Evaluation results confirmed the effectiveness of the proposed technique and the feasibility of its highly accurate positioning.