 Radar
This is the third or even fourth fairy godmother that could pave the way for true autonomous driving. The Israelis around Mobileye want to have the four systems camera, lidar, radar and perhaps infrared each explore the
environment individually and first compare the results with each other. This could mean that a radar system has the same burden of responsibility as the other three systems too.
| Radio Detecting and Ranging |
However, the strengths and weaknesses of the individual systems are distributed. In contrast to camera-based systems, a radar system can deliver relatively good results even in darkness, rain and fog. Even larger
distances are not a problem, considering that the airspace around an airport can be monitored for up to 100 km.
The picture above shows a radar reflector. To understand it better, consider the intersection point in the middle to be further back. Then it becomes understandable that three metal sheets are each joined together at an
angle of 90°. The purpose of the design is to reflect any received radar waves parallel to their arrival, if possible without any major lateral displacement.
| Here is a mid-range radar sensor, almost identical in construction at the front and rear. |
Who needs that? This relatively small funnel, which can be covered by the palm of a hand, is aimed at a radar device (pictured above) on the vehicle. If it is in the right place and focused at this, it can use its actuator part to
send radio waves in a variety of directions until it detects with its sensor those reflected by the funnel shown above.
This process is also called 'calibration'. By the way, this is the part of the workshop work that the device does alone. Such work is always necessary when something has happened to the radar actuator/sensor, for example it
has been moved due to an accident or even replaced. The calibration relies on a fairly precise positioning of the funnel.
For modern workshop work, screwing takes a back seat. Exact measurement is much more important. A lot of space is also required, for example several meters to the rear. The aids include a rod that must be aligned
exactly parallel to the rear axle at a defined distance. After all, measuring tapes that roll up easily on both sides of the rod make measuring processes easier.
Once again, auxiliary devices with laser light are applied to the rear axle, which is of course assumed to be 100% correctly aligned. If in doubt: wheel alignment. The rod can now also be aligned laterally. And finally, a kind of
template is required for each vehicle that determines the position of the reflector relative to the previous measuring device.
Radar has been around for a very long time, not just since people tries to use it to catch traffic offenders. The Second World War gave a decisive boost to development. The picture above shows towers with antennas for
long-distance measurements. There is a certain sensitivity of radar when solid objects block the clear path. Metal in between is the least favorable.
While the first radar devices still had output devices as shown above, the technology developed early on to so-called imaging processes, which were used in war, for example, to assign approaching aircraft to friends or
enemies. Since the electronic signals practically reach the speed of light, movements can of course also be recorded through many measurements in succession.
kfz-tech.de/YBe3
According to the German Brockhaus, radar is a 'radio determination and distance measurement, a positioning method or system that works with radio waves of small wavelengths (decimeter to millimeter waves), for which
it is characteristic that the radiation emittance is directional and the radiation received is the response (direct or indirect echo) to the one sent out. The importance of radar technology is that it is better suited than any other
positioning technology for the detection, measurement and tracking of ships, aircraft and spacecraft in terms of weather independence (largely), accuracy and reliability.'
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