The Record and Replay Approach for GNSS Receiver Performance Assessment in Road Environment

Nowadays the concept of smart transport, that exploits Intelligent Transport Systems (ITS) technology, plays a fundamental role in our society. The Global Navigation Satellite Systems (GNSS) have significant potential in the development of ITS where the estimation of the vehicle’s position represents a key role. However, in strongly constrained environments, such as city centers, the definition of positioning performances is a challenge due to the variability of the different urban scenarios, the modeling of the dynamics as well as the architecture of the positioning platform, which might embed other sensors and aiding means to the GNSS unit. Moreover, the performance metrics of interest are not just position and speed but metrics related to the integrity/reliability concept, properly defined for the road environment. These performance metrics are becoming of paramount interest, as safety-critical application emerging, and have to be assessed. This framework asks for a deep understanding by the ITS sector of the achievable performance by GNSS systems in the different scenarios for automotive. In fact, positioning is taken as a fully reliable and accurate information, based on which more and more automated driving operations are performed. For this reason, the need of standardized performance metrics for GNSS-Based Positioning Terminal (GBPT) and the associated performance assessment procedures and scenarios assume considerable importance. The main focus of the paper is to introduce a performance evaluation procedure based on a record and replay approach able to represent meaningful and realistic scenarios. This approach requires proper data collections that allow the replay phase and data postprocessing to test the GBPT performance. The paper presents also some results obtained on a set of field tests related to different scenarios, selected as representative of reference scenarios for the Key Performance Indicators (KPIs) assessment.