ITS World Congress, Stockholm, 2009 1/8 Grush, et al GMAR STANDARD PERFORMANCE DEFINITIONS FOR GNSS ROAD USE METERING BERN GRUSH 1 , JOAQUÍN COSMEN SCHORTMANN 2 , CARL HAMILTON 3 , MIGUEL ÁNGEL MARTÍNEZ-OLAGÜE 4 1. Skymeter Corp, Toronto, Canada, bgrush@skymetercorp.com +1 416 673 8406 2. GMV, Tres Cantos, Madrid, Spain, jcosmen@gmv.es +34918072160 3. Policy Technology, Stockholm, Sweden, carl.hamilton@policytechnology.com 4. GMV, Tres Cantos, Madrid, Spain, mamartinez@gmv.es +34918061609 ABSTRACT GMAR has just released a partial first draft framework for performance measurement of GNSS road use metering systems, setting quantitative and testable performance metrics, which may be used to test and compare GNSS metering products and services. This partial draft includes: Charging Integrity and Charging Availability. We assert that these performance requirements are particularly critical for defending evidentiary weight, and potentially legal admissibility. GMAR is an independent industry body, proposing a framework that will support comparisons whether between vendors and test locations or over time for a particular vendor. It leaves setting of fixed performance standards to the buyer. Keywords Charging reliability, GMAR, GNSS, GPS, Multipath, Performance standards, Privacy, Road pricing, Road user charging, Security, Tampering, Urban canyon error INTRODUCTION In recent years there has been increased interest in Road User Charging as a means to finance construction and maintenance of roads and to internalize external effects, such as congestion and pollution. To support the increasing complexity of charging schemes, road owners are increasingly looking to use advanced technology based on Global Navigation Satellite Systems (GNSS), such as GPS and Galileo. GNSS-based charging is new, complex, and has evidenced difficulties in urban signal environments. Components for positioning, data processing, and communication from different manufacturers, designed for different types of use, can be integrated into packages intended to meet requirements for systems producing legally binding financial records. Accordingly, several companies are patenting and building systems using multiple approaches and architectures, making simple head to head comparisons difficult. Because GNSS signals are affected by satellite and atmospheric errors and can be easily deflected or blocked in dense cities and steep terrain, these systems must mitigate satellite positioning errors to be reliable. None are more troublesome than site-specific multipath known as ‘urban-canyon’ error. This error can be influenced by time-of-day, nearby