Semiconductors are stepping up to meet the challenge of active automotive safety systems. As crash detection begins to merge with other electronics in the vehicle, such as communications and advanced driver assistance, the automobile is becoming more autonomous and more intelligent. Electronic systems that can act faster than the driver will be able to take control to reduce the severity and frequency of accidents, saving lives on the roads.
In the area of active safety, systems enabled by radar technology are becoming more prevalent. Adaptive Cruise Control (ACC) allows the driver to set a safe "follow distance" to the car in front of him or her, and automatically accelerates and decelerates the car to keep that follow distance constant. Some systems also include automatic braking features that will apply the brakes if the car in front stops quickly or if an object blocks the road. Likewise Blind Spot Detection systems can also depend on radar.
As in-car radar moves from being a luxury option to a standard safety feature, and from high-end to mid-range cars, the adoption and growth rates depend on the system cost. As radar becomes more affordable, and offers better performance in terms of target classification and range resolution, it will become a more popular option.
For system designers, there is a need to add these safety features without incurring substantial cost while still meeting the automotive industry's stringent quality requirements. Additionally, the radar sensor module must be kept small enough to fit into areas of the car, such as behind the bumper, which were not originally designed to house such electronics.
For the complete article as to how a compact integrated radar front end helps meet such challenges, click here, courtesy of Automotive Designline Europe.
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The matter for this auto safety is very much depending on other driver. Driving is not a safe task, although I am doing all the best to prevent an accident from happening. Like two hand on wheel, look front, donít talk, donít eat, donít drink, donít sleep can not prevent it many accidents. It is because other driver made mistakes. All of those safety devices are sensing a very near range, like side, front, and back. The defensive driving is the best way a diver can do. If this kind of technology can help or warn a lack of attention on detail it will be super.
Can anyone tell why 12 bit 80Msps ADC with mux (so ~13Msps per channel - assuming no latency) is a good solution to the radar? I mean what factor dictates the sampling rate of the ADC? Is 67dB SNR good enough? Again, what is the baseline performance requirement that let ADI to make such product?
GREAT-Terry, this is Sam Weinstein of Analog Devices, one of the authors of the article. You are correct that the user can achieve a sample rate of ~13MHz per channel with the AD8283 (or higher if less than 6 channels are used). Radar systems work by sending out a frequency sweep and ďlisteningĒ for the echo. Minimum ADC sample rate is dictated by the baseband signal frequency content, which is the echo signal mixed with the transmit signal. Received baseband signal bandwidth depends on sweep rate, sweep frequency content, and maximum target distance (range). For example, a sweep rate of 50us, sweep frequency content of 100MHz, and a range of 150m corresponds to a 2MHz BW. You want the sample rate per channel to be about 3x or 4x the frequency of this, or about 6 to 8 Msps. Regarding your other question, SNR of the AD8283 is one of many factors that affect the overall system accuracy. SNR, among many other specifications, were closely worked out with our customers who are building automotive radar systems.
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