The European PRoPART (Precise and Robust Positioning for Automated Road Transports) project, funded by the European Global Navigation Satellite System Agency (GSA), recently successfully demonstrated its highly accurate positioning system in a recreated motorway situation at the AstaZero test area in Sweden, with a connected autonomous truck and two unconnected manned cars.
As part of the test, the Scania self-driving truck executed a safe and efficient lane change in traffic. The maneuver was managed by the new system, relying on centimeter-level positioning combined with collaborative perception sensor data.
The project demonstrated that it was possible to pinpoint the position with ten-centimeter (3.94 inches) accuracy. The truck could execute the maneuver due to the precise positioning and an accurate representation of the whole surrounding environment. This was achieved by fusing data from the truck’s camera and front and side radars combined with radars mounted on roadside units.
The project combined RTK Positioning Software from Waysure (Sweden) with satellite measurements, in particular advanced Galileo signals for improved accuracy and authentication from Fraunhofer IIS (Germany). The satellite positioning has been augmented with an Ultra-Wideband (UWB) ranging solution from Spanish research institution Ceit-IK4.
The self-driving truck was supplied by Scania, with Hungary-based V2X company Commsignia providing in the C-ITS technology. Baselabs from Germany provided sensor data fusion of onboard and road-side sensors and developed a situational assessment for the intended automated lane change maneuver. The project was coordinated by the Research Institute of Sweden (RISE).
Ordinarily, autonomous vehicles rely on their own sensors to interpret and process data on the surrounding environment. However, noted Project Coordinator Stefan Nord, RISE:
In addition to positioning, we’ve also added infrastructure-to-vehicle communications. If vehicles share information, you can extend their horizon and benefit from data from another vehicle to also look around the corner and thereby gather more data as a basis for maneuvering decisions.
Scania is presently investigating several different positioning solutions, said Fredrik Hoxell, a Development Engineer at Scania Intelligent Transport Systems.
In the project, we focused on achieving a positioning error below 20 centimeters in combination with an ambitious target integrity risk—that is, the probability of the position error exceeding this error limit. However, for deployment in real-life traffic situations, which tend to be much more dynamic and unstructured, there are of course many more vehicle and system characteristics and possible sources of errors that need to be handled.
Reliable and high-integrity navigation is absolutely essential when operating autonomous vehicles in uncontrolled environments. These trials offer one possible facet of the overall challenge related to navigation support on the journey towards safe and sustainable autonomous transport.—Fredrik Hoxell