One of the primary assets autonomous vehicles will need are accurate roadmaps to perform tasks like figuring out what streets and highways to take, where to expect stop signs and traffic lights, along with determining speed limits. Self-driving cars are equipped with onboard sensors like LiDAR and cameras, which help them develop thorough virtual maps to navigate through their routes. It’s no question these maps need to be accurate down to the last centimeter, and use algorithms to develop some redundancy so the vehicle’s map, sensors, and GPS can help determine where the car is headed.

Future navigational maps for self-driving cars may be in store for an accuracy boost from a newfound partnership between German-based engineering and electronics company Bosch and mapping company TomTom. Both companies have joined forces to work on what’s being described as a “radar road signature,” an idea deriving from vehicles being manually (and autonomously) driven to use onboard radar sensors for intricately mapping roadways. The conventional radar sensors Bosch plans to use are already included with some cars for functions like adaptive cruise control, which helps a vehicle maintain proper distance from other vehicles.

According to Bosch, cars containing radar sensors could begin collecting data that would be integrated into TomTom maps as soon as 2020. Bosch Board of Management Member Dirk Hoheisel thinks they’ll need fleets of vehicles to achieve their ultimate goal.

“We currently expect that we will need fleets for freeways in Europe, North America, and Asia Pacific…” Hoheisel says. “Each could consist of around one million vehicles in order to keep our high-resolution map up to date.”

Bosch’s radar sensors can see over 800 feet, function at night, and in poor visibility conditions. Ideally, a car manufacturer will use its own cloud to accumulate data from a vehicle’s radar sensors that they’ll share with Bosch and TomTom. One of Bosch’s initiatives entails using radar to detect motionless objects like road signs, since current radar sensors primarily focus on mobile objects like other vehicles. As a result, this signifies how existing radar sensors need to be modified.

Mertz of Carnegie Mellon notes how an intriguing aspect of the Bosch/TomTom collaboration is that radar sensors are already in many vehicles, but imperfections still exist in each sensing system.

“Maps are outdates the second you write them down,” says Mertz, who also acknowledges how vision systems are hindered during the night, but anticipates radar will continue having flaws of its own to deal with.

Executive Director of the Center for Automotive Research at Stanford Stephen Zoepf says the initiative signifies a step in the right direction.

“The Bosch/TomTom partnership can help create more detailed maps,” says Zoepf. “But it will be years before the information can be incorporated into production navigation systems or self-driving vehicles.”