Swedes probe ways to enhance self driving accuracy

Volvo is using road magnets for positioning of self-driving cars.

Volvo Car Group has completed a research project using magnets in the roadway to help the car determine its position.

The research, which has been financed in strategic co-operation with the Swedish Transport Administration (Trafikverket), is a potential key to the implementation of self-driving vehicles.

Reliable and highly accurate positioning is one of the crucial issues in the development of self-driving cars.

While established positioning technologies such as GPS and cameras have limitations in certain conditions, road-integrated magnets remain unaffected by physical obstacles and poor weather conditions.

"The magnets create an invisible 'railway' that literally paves the way for a positioning inaccuracy of less than one decimetre. We have tested the technology at a variety of speeds and the results so far are promising," says Jonas Ekmark, preventive safety leader at Volvo Car Group. Volvo Cars has a large-scale autonomous driving pilot project in which 100 self-driving Volvo cars will use public roads in everyday driving conditions around the Swedish city of Gothenburg.

"Our aim is for the car to be able to handle the driving all by itself," explains Ekmark.

Volvo Cars' research team created a 100-metre long test track at the company's testing facilities in Hallered in Gothenburg, Sweden. A pattern of round ferrite magnets (40x15mm) was located 200mm below the road surface.

The car was equipped with several magnetic field sensors.

The research programme was designed to evaluate crucial issues, such as detection range, reliability, durability, cost and the impact on road maintenance.

See page 29 for a story on how the California Department of Motor Vehicles is dealing with driverless cars