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Normally, Emma and I work as a pair. We’re junior reporters for Genius, Daimler’s initiative for STEM education, and we investigate the world of Daimler.
This time around, we operated differently. Emma had already found out all about the fuel cell on her own, so this time Florian Baumgärtner invited me to visit him in the Radar Hall. The first thing that struck me was the strange black walls…
What is radar, and how does it work?
Florian greeted me and showed me what he had prepared. Inside the Radar Hall were a car and various illustrated charts. He used these to explain to me what radar is and how it works
I can imagine that it’s similar to bats, which emit squeaks and use the echoes to identify their surroundings. It’s the same principle as the one behind radar, except that radar emits electromagnetic waves instead of sounds. The sensor measures which waves bounce back and how quickly they bounce back. That’s how it “perceives” its surroundings. Sensors of this kind had also been integrated into the car that was standing in the hall.
A robot draws a picture
Standing in the center of the room was something that looked like a huge pillar. Florian said it’s a robot. What could it do? The robots that Emma and I got to know at the IAA looked very different. Florian pushed a button and the robot started to move. It slowly rolled through the hall, buzzing as it went. I watched it closely, but I still couldn’t figure out what it was doing.
When the robot had finished its task, Florian picked up a printout. Aha — the radar sensor had measured the entire route along which the robot was moving. Florian asked me whether I recognized the shape on the printout. What a question! The printout showed wobbly measuring lines, but of course I saw at first glance the route that the robot had taken. It was a Mercedes star. The robot had in effect “drawn” a picture.
Florian explained to me that this way he and his colleagues can test the precision of the sensor’s measurements. In the places where the lines on the printout are especially wobbly, the measuring was a bit less accurate. That’s how Florian knows where he has to do some more work on the sensor’s settings.
Safety, even in the blind spot
Next, I wondered what these findings were good for. After all, there aren’t any robots rolling around in road traffic and drawing shapes on the asphalt. The next thing we looked at was the car that Florian had driven into the hall. We climbed in, and right away he showed me how this technology actually makes road traffic safer.
For example, when a woman riding a bike directly passes the car, she enters a “blind spot.” It’s a place where, just for a moment, she can’t be seen at all by a person sitting in the car. Opening a car door at exactly this moment would be very dangerous. The radar sensor is there in order to prevent such accidents from happening. Right away, we tried it out. The woman rode her bicycle past the car, but before I could open the door the car warned me by sounding a signal. I was thrilled! This radar sensor system is really useful — and absolutely important.
Invisible to radar
But what were those black walls all about? They look that way because they’ve been covered with special mats with odd spikes and points all over them. These mats absorb the radar waves so that the sensor can’t recognize them. That way the engineers make sure that only the things they need to know are actually measured by the radar.
I could hardly wait to ask my next question: Could I also become invisible to the radar? Of course, said Florian. That too would work because of the black mats. If a person were to wrap himself in them, the sensor would no longer be able to detect him. Of course I had to try that out right away! It looked funny — but it wasn’t very comfortable…