TomTom and Bosch announced at the TU-Automotive show in Detroit the creation of an HD map with integrated Radar Road Signature layer for the localization of vehicles in autonomous driving. The Radar Road Signature layer will allow automated vehicles to determine their exact location on a road down to a few centimeters, working in conjunction with the TomTom HD Map.

Harold Goddijn, CEO of TomTom, said: “We’ve been working hard to create the HD Map needed for autonomous driving, including localization attributes such as TomTom’s RoadDNA. It’s exciting to be launching this additional localization layer with Bosch in the form of the Radar Road Signature – that greatly increases the robustness of localization under all circumstances.”

“The Radar Road Signature is a milestone on the path towards automated driving. It will enable automated vehicles to reliably determine their location at all times,” said Bosch board of management member Dirk Hoheisel.

Bosch said it wants to launch the Radar Road Signature onto the market in Europe and the U.S. by 2020 at the latest.

According to the company, Bosch’s Radar Road Signature is made up of billions of individual reflection points. These are formed everywhere that radar signals hit – for example, on crash barriers or road signs – and reproduce the course a road takes. Automated vehicles can use the map to determine their exact location in a lane down to a few centimeters.

The two companies have been working on the radar road signature and its integration into TomTom’s high-resolution overall map since the beginning of their collaboration in July 2015. The main challenge was finding a way to adapt existing radar sensors for this task. When used in a driver assistance system such as automatic emergency braking systems or adaptive cruise control (ACC), the sensors detect moving objects. But in order to generate the radar road signature, they also need to be able to detect static objects, which meant that existing radar sensors had to be modified. The next generation of Bosch radar sensors will be able to provide the data required for the radar road signature. “Cars arriving on the market in years to come with the assistance functions of tomorrow will be running the map for the automated vehicles of the future,” Hoheisel said.

According to the company, high-resolution maps are essential for automated driving and provide information that goes beyond the area that sensors are able to monitor. Unlike maps for today’s navigation devices, they are made up of a number of overlapping layers:

Localization layer: An automated vehicle can determine its position in a lane by using a localization layer comprising the Bosch radar road signature plus an additional video localization map. It compares information about objects that it has received via its surround sensors using the corresponding information from the localization layer. In this way, the vehicle can determine its relative position to these objects.

Planning layer: The planning layer is used to calculate individual maneuvers during automated driving (trajectory planning). The planning layer also contains information about the course of the road, traffic signs and speed limits, as well as bends and gradients. An automated vehicle can use the planning layer, for example, to decide when it should change lanes.

Dynamic layer: Information about any rapidly changing traffic situations such as traffic jams, construction work and hazards, or available parking spaces is saved in the dynamic layer.

“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,” said Hoheisel.

Current data for each of the layers will be generated by the vehicles’ on-board sensors while they are driving. Communication boxes such as Bosch’s Connectivity Control Unit will transmit the radar sensors’ data from the vehicles to the manufacturers’ cloud and then on to the Bosch IoT Cloud. Bosch will use this to create the radar road signature, which is compatible with all conventional map formats. TomTom’s responsibilities will include integrating the radar road signature in the overall map and distributing it.