3 ms·

I haven't worked with automotive radars but the way it works in aeronautical radar is that you apply frequency binning in the electronics and ignore returns tha

I haven't worked with automotive radars but the way it works in aeronautical radar is that you apply frequency binning in the electronics and ignore returns that have the wrong Doppler shift at the waveform level, long before step A in the article. If you didn't do it this way your computer would be overwhelmed considering every tree and house you can see but only moving objects like airplanes. It's the same principle as the way your eyes only report things that move over your retina as your eye moves, letting you filter out imperfections in the lens of your eye and your blind spot. Similarly, I assume that the computers in a car would be overwhelmed by the task of taking the returns from every single post on a guardrail and sorting them into distinct objects before deciding to ignore them due to relative velocity so I'm fairly sure that a similar mechanism is at work within the hardware of the radar unit the Uber car. So given that the woman showed up on Uber's sensors she would have been detected by the camera system or the lidar. And apparently she was detected.

wilburTheDog 9y ago
Thanks for the explanation. I hadn't heard of frequency binning(1) before. It makes sense that stationary objects would be filtered out before they even reach the signal processing software. But Uber did seem to be relying more heavily on radar than the other sensors. From an article I linked in another comment "the number of LIDAR sensors were reduced from five to just one – mounted on the roof – and in their place, the number of radar sensors was increased from seven to 10. Uber also reduced the number of cameras on the car from 20 to seven." And for LIDAR this "results in a blind spot low to the ground all around the car." They had to know radar wouldn't detect stationary objects. So the signal processor should be prioritizing camera and LIDAR reports of anything stationary in the road. If it really was programmed to ignore such a signal it seems like gross malfeasance to me. If not, then the speculation in the linked article is incorrect and it's the same problem Tesla's system has. 1. https://www.eetimes.com/document.asp?doc_id=1278779 https://www.eetimes.com/document.asp?doc_id=1278779

wilburTheDog 9y ago

Thanks for the explanation. I hadn't heard of frequency binning(1) before. It makes sense that stationary objects would be filtered out before they even reach the signal processing software. But Uber did seem to be relying more heavily on radar than the other sensors. From an article I linked in another comment "the number of LIDAR sensors were reduced from five to just one – mounted on the roof – and in their place, the number of radar sensors was increased from seven to 10. Uber also reduced the number of cameras on the car from 20 to seven." And for LIDAR this "results in a blind spot low to the ground all around the car." They had to know radar wouldn't detect stationary objects. So the signal processor should be prioritizing camera and LIDAR reports of anything stationary in the road. If it really was programmed to ignore such a signal it seems like gross malfeasance to me. If not, then the speculation in the linked article is incorrect and it's the same problem Tesla's system has. 1. https://www.eetimes.com/document.asp?doc_id=1278779 https://www.eetimes.com/document.asp?doc_id=1278779