A ls Micheal Jackson 1983 the first time the moonwalk Song Billi Jean danced, there was amazement in the audience. Today the King of Pop could have caused even more excitement with his famous dance step when the trunk lid of a car pops open at the same time as the show. More precisely, the trunk of an Arteon, which Bernd Ette from the advance development department at Volkswagen has equipped with the new UWB radio chip modules from the Dutch semiconductor giant NXP.
Runtime instead of signal strength
UWB stands for Ultra Wide Band Frequencies in the range of 6 to 9 GHz and - unlike most of the other widespread radio standards such as WLAN or Bluetooth - allow very precise location. 'With UWB, we can determine the position to within three centimeters - in milliseconds,' explains Lars Reger, CTO at NXP. The technology is so precise because the localization is calculated over the duration of the signal and not over the signal strength, as is the case with WLAN, Bluetooth or other UHF signals (ultra-high frequencies 0.3 to 3 GHz) as with most current radio keys .
You have to imagine it like this: The UWB transmitter in the car key sends an encrypted, digital signal to the car at the speed of light. The car then signs the signal and sends it back to the key in a modified form. The chip in the key now knows how much time between sending and receiving the signalhas passed. The allotted time that the car needs to calculate the signature is then deducted and the chip in the key can calculate the radius in which the car is located. If you now use several UWB units in the car, you can calculate their relative position to each other in space. This way the key knows whether it is near the trunk, the driver's door or the right headlight.
Fusion of various sensor information
That brings us back to the moonwalk. 'For our test setup, we placed five UWB modules in the car. One each in the doors and one on the trunk,' explains Bernd Ette, who has been working on this technology for a year. 'In addition to the UWB chip, we also built gyro and accelerator sensors in the key, as can be found in every smartphone today.' By merging all sensor information, it is then possible for the developer to recognize not only the position of the key, but also movement patterns. Like dance steps.
So it doesn't matter whether you dance the moonwalk, a waltz or disco fox to open the trunk, or just turn to the car or stomp your foot twice. If the key is in a certain position and has identified a movement that is to be recognized, it sends an 'open' command to the car. 'We can easily teach the key these movements by activating the learning mode and showing them to it,' the developer describes the process. At the beginning the detection is not yet perfect, but the system learns each time and gets better and better.
From kick kick to child seat
With the ultra wide band technology much more is possible. For example, the use of such modules in child seats could automatically deactivate the airbags. 'Thanks to the position and motion sensors, the system can also detect whether the seat is installed correctly or too steeply,' explains Ette, who also worked on the Audi system a few years agoopens the trunk with a kick gesture. 'For most situations, three of our UWB modules should be sufficient, which is why we deliberately did not permanently install our five sensors on the car. So we can use them outside the car,' he continues.
A simple scenario, for example, would be to extend the electric towbar as soon as the appropriate trailer moves towards the car to which one of the modules is attached. 'But that is far from over,' says Ette with certainty. Another application would be the automatic coupling to a trailer. 'To do this, one would simply have to attach one of the modules to a defined location on the trailer and expand the automated parking assistant so that it comes to a stop directly with the trailer coupling under the drawbar.'
UWB chips in the smartphone
So much for the things that VW developers can imagine. When it comes to NXP, that's not all. Because UWB has a range of around ten meters, which makes it interesting for use in the infrastructure of cars. Garage doors could be opened automatically when the car approaches, or the system sounds an alarm if, for example, you accidentally forget your smartphone, briefcase or other items in the car. 'To do this, they just have to be equipped with a small chip that is barely larger than a euro coin,' says Lars Reger from NXP. 'And I am sure that it will not be long before the UWB chips also get into the smartphone. Then a car key would not even be needed to open the car.'
To ensure that these ideas do not remain a dream of the future, the FiRa consortium was founded at the beginning of August. In addition to chip manufacturers such as NXP and auto suppliers such as Bosch, consumer electronics giants such as Samsung and Sony are also involved, so there is a good chance that the standard will also spread in other devices that are in the world of the Internet of Things (IoT ) move.