Evaluation and comparison of GNSS navigation integrity monitoring algorithm for urban transport applications
Résumé
From road guidance applications to locomotives or road vehicles fleet management, Global Navigation Satellite System (GNSS)-based positioning systems are more and more spread and used. However, the urban environment presents great challenges for GNSS positioning since number of obstacles result in signal attenuations and blockages, which can cause large errors. Yet, for new GNSS land applications, knowing the certainty of one's localization is of great importance if we want to rely on it for toll, insurance or for railway signaling. The concept of GNSS integrity, which is defined as a measure of trust to be placed in the correctness of the information supplied by the total system, can help to meet this requirement. Although GNSS integrity has been firstly developed and formalized in the aviation field, the algorithms developed for the aerospace domain cannot be introduced directly to the GNSS land applications. This is because a high data redundancy exists in the aviation domain and a basic hypothesis that only one failure occurs at a time is made for aviation schemes, which are not the case for the urban users. It is a great challenge to extend the integrity monitoring algorithms to GNSS urban applications. This paper will highlight the need for new integrity monitoring systems and will illustrate the behaviour of existing solutions based on real data. In this paper, we will in particular compare and evaluate the performances of several Fault Detection and Exclusion (FDE) integrity monitoring algorithms as well as different weighting models.