Integrity provision for map-matched positioning of road vehicles at lane level

Many road safety applications and those with critical performance restrictions (such as satellite based electronic fee collection) demand from the onboard navigation systems, on the one hand, positions referred to a local map, and on the other hand, an indicator of the quality of these positions, the so called integrity. The map-matched positions are commonly estimated in two separated phases: firstly, position is determined by means of GNSS (in occasions assisted by odometry or inertial sensors) and secondly, a map-matching process is performed based on the position estimated previously. However, current common integrity indicators, imported from the aerial domain, only represent the quality of the GNSS input, and not the final combined map-matched position. The influence of the information coming from other sensors and maps is neglected, with negative consequences in the coherence between positioning and integrity. This paper presents a solution to the problem of integrity provision in a combined positioning and map-matching process, based on two complementary integrity parameters. To the best of the authors´ knowledge, this is the first work that presents integrity monitoring of the complete navigation process, unifying both map-matching and positioning. Our proposal has been tested in real experiments in Germany, proving the validity of the concept, and its suitability to the problem under consideration.