Accuracy Analysis for GNSS-based Urban Land Vehicle Localisation System

The future of Intelligent Transportation Systems (ITS) relies on a properly constructed Control Transportation System (CTS) based on a dynamically accurate localisation system. To ensure quality of the localisation system data-fusion algorithms are applied to enhance trueness and precision of the provided locations. But that quality is directly related to the accuracy of the Global Navigation Satellite System (GNSS) receiver. Nowadays Global Position System (GPS) is not the functional GNSS system over Asia. Even though the second generation of China’s BeiDou Navigation Satellite System (BDS), also known as COMPASS, is still under construction on a global coverage, it provides service since the beginning of 2013 to the Asia-Pacific region. Focusing on urban scenarios applications, this paper analyses the accuracy of BDS receivers to provide location for localisation systems in urban scenarios, comparing it with GPS and the combination of both in a Multi-GNSS system, using a Differential GNSS (DGNSS) as a reference for the accuracy results. From the accuracy limits results further reliability analysis by means of trueness and precision for tangential and perpendicular coordinates in the dynamic frame of vehicles were proposed. The results show that a circular error probable (CEP) approach is not a realistic representation of the dynamic behaviour of the receivers. So the new Mahalanobis Ellipses Filter (MEF) approach was tested and proven to be a better dynamic accuracy representation for land vehicles, making it the best approach to describe accuracy requirements for BDS-based urban land vehicle localisation systems for safety-relevant ITS.