NAVI CAMPUS: GPS –IMU application for helping visually impaired people to navigate in university campuses
Jesus Zegarra(1),*, Laurence Rasseneur(1) , René Farcy(2)
(1) Faculté des Sciences du Sport, Université de Strasbourg, 14 rue René Descartes, 67084 Strasbourg Cedex (2) Laboratoire Aimé Cotton, Université Paris-Sud, ENS Cachan, CNRS, Université Paris-Saclay, 91405 Orsay Cedex, France
*email@example.com , Tel: +33 (0)3 68 85 64 51
Current GPS devices are sensible to interferences in urban areas and its heading in pedestrian navigation (low speed) is not precise. If a visually impaired person hesitates and loses his orientation, he has to walk with the GPS a few tens of meters in order to have an updated heading. Moreover, the GPS devices are based on routes from the maps, however, in the case of a campus, the addresses of a faculty building are not easy to find, if it exists the information is not adapted for a blind person. In this article, the authors propose a solution to allow the visually impaired person to navigate outside and inside the buildings in the Central Campus of the Strasbourg University. In order to give the possibility, for the visually impaired person, to walk from one building to another or from a public transport station (tramway or bus) to the main entrance of a building without sighted intervention, the authors have developed Navi Campus which is a Smart Phone application that combines the information coming from the GPS and from the IMU sensors (accelerometers and gyrometers) and a compass to guide the person. The application calculates a path automatically from the current GPS coordinates of the person to the GPS coordinates from the destination. Navi Campus gives a clockwise heading, follows the change of course heading of the person even in case of hesitation and also gives the distances in a more precise way adapted to the specific needs of the blind people guidance. The vocal information is given in the way of “ heading “ and “ distance ” taking into account the body axis walking direction of the person. For example, the information “12 o’clock, 100 meters” means that the person has to walk straight during 100 meters. Another example, “ 3 o’clock, 50 meters” means that the destination is on the right of the person in 50 meters. While approaching to the destination, the distance decreases allowing the person navigates from GPS point to GPS point. In the case of indoor navigation, where the GPS signal is not available, Navi Campus thanks to the information coming from the Inertial Measurement unit (IMU: accelerometers and gyroscopes), compass and barometer, allows to guide in the small and vast indoor places. The guidance is performed from functional paths recorded before and the instructions given allow correcting the trajectory of the visually impaired person when he goes out from the predefined path.