Bosch and TomTom Determine the Vehicle Position Using Radar Signals
The supplier Bosch and Dutch map and traffic information provider TomTom have succeeded in using radar signals to create a localisation layer, which is indispensable for HD maps. So far, video data has been used for this purpose. Based on the localisation layer in high-resolution maps, an automated vehicle can determine its position in a lane.
Bosch’s “radar road signature”
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 thereby use the map to determine their exact location in a lane down to a few centimetres, Bosch explains.
“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”, says Dr. Dirk Hoheisel, Bosch board of management member. The main advantage of Bosch’s radar road signature is its robustness: unlike maps that rely exclusively on video data for vehicle localisation, localisation with the radar road signature also works reliably at night and even in poor visibility. Moreover, Bosch’s radar road signature only transmits five kilobytes of data to a cloud per kilometre. This data volume is twice as high using a video map. Bosch expects that by 2020 at the latest, the first vehicles will provide data for the radar road signature in Europe and the US.
Radar sensors have been modified
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 modify 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. However, they also need to be able to detect static objects in order to generate the radar road signature, which means that existing radar sensors have to be modified. The next generation of Bosch radar sensors will be able to provide the data required for the radar road signature.
One million vehicles keep the high-resolution map up to date
“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”, says Hoheisel. Using on-board sensors, the moving vehicles generate current data for the individual layers: in addition to the localisation layer, these are the planning and dynamic layer. Communication boxes such as Bosch’s Connectivity Control Unit will transmit the radar sensors’ data from the vehicles to the manufacturer’s cloud and then on to the Bosch IoT Cloud. Bosch will use this to create the radar road signature, which is to be compatible with all conventional map formats. TomTom’s responsibilities will include integrating the radar road signature into the overall map and distributing it.