Re:Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow
by apcragg on Tuesday September 18, 2018 @07:15AM
(#18014203)
Small nitpick. The range resolution improves with increasing pulse/chirp/waveform bandwidth, not increasing carrier frequency. It's true that at higher carrier frequencies there is more bandwidth available and thus better range resolution is possible but the relationship is slightly different than "delta_r ~ frequency"
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Re:Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow
by rademacher on Tuesday September 18, 2018 @07:46AM
(#18014344)
The relationship is cT/2, where c is the speed of light, and T is the pulse length, if the waveform is CW. Note that in this case T can limit the minimum range you can detect. Or you can use c/(2B) where B is the bandwidth of the signal as you stated. I believe the limit is wavelength/2 for resolution though.
Re:Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow
by apcragg on Tuesday September 18, 2018 @01:27PM
(#18017283)
Yup. And in order to get a pulse of T you need, at best, a sinc window. Resolution is intrinsically linked to bandwidth.
Re:Self-Driving Cars Can Handle Neither Rain nor Sleet nor Snow
by Animats on Tuesday September 18, 2018 @02:39PM
(#18017952)
Range resolution isn't the problem. Angular resolution is.
Here's a video of what's claimed to be one of the higher resolution radars.[1] About one degree. It can see cars.
Many new startups in this area.[2] Most are operating in the 77GHz range, which is OK for sensing other cars but marginal for smaller targets. LIDAR-type resolution is still a ways off.
[1] https://www.youtube.com/watch?v=r0s5P1SQ34M [2] https://www.mwrf.com/systems/startups-trying-revamp-automoti...