Self-driving cars need accurate maps. They need to know what roads to take to get from one place to another, but they also need to know where to expect a stop sign, for example, or what the road’s speed limit is. Onboard sensors, like LIDAR and cameras, give the car situational awareness, and the map is a complement to those.
The maps should ideally be accurate down to less than an inch, says Christoph Mertz, a scientist at the Robotics Institute of Carnegie Mellon University and cofounder of a road monitoring company called Roadbotics. “You want the systems to be redundant,” Mertz says, so that the map, GPS, and onboard sensors can help the car figure out where it is.
Maps of the future may get an accuracy boost, thanks to a new partnership between Bosch and mapping company TomTom; they are collaborating on a technology they call a “radar road signature.” The idea, announced on Wednesday, is that cars driven by humans (and possibly autonomous ones as well) will use onboard radar sensors to map the roads in a highly-detailed way. Indeed, the same general type of radar sensors that Bosch plans to use for this initiative are already included with some cars—for example, in an adaptive cruise control system that helps your vehicle keep the right distance from the car in front of it.
Bosch said that by 2020, cars with radar sensors could start collecting data that would be integrated into TomTom maps. “We currently expect that we will need fleets for freeways in Europe, North America, and Asia Pacific that each consist of around one million vehicles in order to keep our high-resolution map up to date,” Dirk Hoheisel, a member of Bosch board of management, said in a statement. Bosch makes radar sensors that can see over 800 feet, and importantly, radar functions at night, or when visibility is crummy.
The idea is that a car manufacturer will gather, in its own cloud, the data gleaned from the radar sensors on a vehicle, and then that information will be shared with Bosch and TomTom. Then those improved maps could help guide autonomous vehicles.
Interestingly, the Bosch initiative involves using radar to look at static objects, like road signs; current radar sensors focus on moving ones, like the vehicle in front of you. That meant that “existing radar sensors had to be modified,” Bosch said in the statement.
Mertz, of Carnegie Mellon, says that a nice aspect of the Bosch plan is that radar sensors are already in cars, but he points out that each sensing system is imperfect. “Maps are outdated the second you write them down,” he says, vision systems are hampered at night, and radar likely has shortcomings as well.
Stephen Zoepf, the executive director of the Center for Automotive Research at Stanford, says via email that the initiative represents “a step in the right direction.”
“The Bosch/TomTom partnership can help create more detailed maps,” he writes, “but it will be years before the information can be incorporated into production navigation systems or [self-driving vehicles].”