GNSS Integrity and Protection Level Computation for Vehicular Applications

The Italian Space Agency (ASI) launched in December 2008 the INFOSAT Project in order to design, develop at prototype level and demonstrate on the field an integrated system based on navigation technologies and devoted to the following application areas: (a) electronic toll collection and accesses control, (b) traffic monitoring and control and prevention, (c) assistance and relief in emergency situations. At present satellite navigation applications dedicated to the road sector are part of a global market sector involving millions of vehicles (cars, buses, trucks…). Satellite navigation technologies can actually enable a broader range of applications within the road sector in particular the so-called “liability critical” applications in which the estimation of the vehicles position can be used to certify economic transactions, as it is the case of tolling applications. The main limitation to the expansion of GNSS applications in these fields is the lack of guarantee on the reliability of the signal in space for the related position solution. Two parallel and competitive Research activities have been initiated within the Project to provide innovative methods of real-time integrity computations to generate integrity information to be used for Emergency situation, toll collection and accesses control: • ALIVE algorithms structured such that they can use all the broadcast information in the various application areas, i.e. RAIM integrated with SBAS information or EGNOS augmented with Local element correction and • EIV that make use of history-based processing techniques in order to help satellite-driven horizontal protection level computation by taking into account constraints on vehicle dynamics and a statistical description of vehicle inertial accelerations.