Seamless Indoor-Outdoor Infrastructure-free Navigation for Pedestrians and Vehicles with GNSS-aided Foot-mounted IMU

With the highly development of navigation techniques during the past decades, the demand for seamless indoor-outdoor navigation is growing from different application fields especially for the military or the first response emergency services. For military applications, one of the key performance requirements is the availability of the positioning solutions for all kinds of dynamics in different environments. Furthermore, due to the stealth requirement in some military actions, it is impossible for military vehicles or personnel to emit signals which enable to be detected by their opponents. This limitation prevents the use of infrastructure-based cooperative localization techniques. The research work of this paper aims at facing the following challenging issues: firstly, to design a positioning filter which is adaptive to the dynamic changes between walking and driving; secondly, to find an approach that correctly identifies the transition between outdoor and indoor with reduced latency; finally, to construct a loosely coupling GNSS/IMU scheme which takes into account the GNSS signal distortion in indoor and urban spaces. Under this context, we propose a complete indoor-outdoor infrastructure-free positioning prototype including a foot-mounted reference navigation system named Pedestrian Reference System (PERSY) and a Ublox High Sensitivity GNSS (HSGNSS) receiver (M8P). A loosely-coupled architecture between GNSS receiver and the PERSY is employed by using an indicator of horizontal position accuracy PACCH provided by the GNSS Ublox M8P receiver. This indicator allows qualifying the position solutions delivered by the GNSS receiver as well as detecting the transition of indoor/outdoor, which helps the PERSY to update with absolute positions from GNSS. This positioning prototype can take advantage of both GNSS and PERSY so as to realize a seamless indoor-outdoor positioning for pedestrians and vehicles. The proposed system is evaluated in two scenarios over respectively 2.17 km and 2.68 km including indoor , outdoor and in-vehicle phases. The median horizontal position errors for the two scenarios are respectively 2.23 m and 1.93 m.