The increased interest in the use of GNSS satellite based systems (GPS and Galileo) for road user charging has led to a plethora of new entrants to the on-board equipment market. Our research has shown that simple GPS systems alone exhibit unsatisfactory levels of positional precision and availability for all but the most elementary charging systems, especially when required to perform in “urban canyon” city environment or where there are parallel roads of different charge classes.

Building Capital bring extensive understanding of the supplementary sensors that may be employed to augment GNSS systems such as:

• multi-axis gyroscopes and accelerometers
• tachograph and CAN-bus interfaces
• magnetometers and motion sensors.
• differential GPS and real-time kinetmatics

Inertial navigation is the selective use (in real-time) of one or more of these sensors to significantly better road charging performance than GNSS alone. Dead reckoning is the capability for the precise position of the on-board system to be tracked even when the satellite signal is degraded or lost.

Our experience comes from the design and development of our Axiom Road User Charging Development Platform, our involvement in most of the major road user charging schemes to date, and through specific technical validation and compliance test processes we have developed. Using our advanced inertial navigation systems we have quantified vendors’ on-board equipment performance in a wide range of operating environments for our clients, providing independent scientific appraisals and risk appraisals which serve to guarantee a successful project implementation.