4 ms·
This sounds somewhat impractical, heres some reasons why: 1. Concrete and asphalt significantly attenuate radio signals, especially reinforced concrete. 2. Bo
by kayfox 8y ago
This sounds somewhat impractical, heres some reasons why:
1. Concrete and asphalt significantly attenuate radio signals, especially reinforced concrete.
2. Both concrete and asphalt expand and contract, and would likely damage the chips.
3. Asphalt isn't exactly solid at all times, compounding the issue above.
4. Reading said chips would be difficult, as they would only be in range for a few tens of milliseconds.
- petee 8y agoGood point on #1 & 4, it'd have to be really near the top, and would need super fast read speeds; although #2+3 would be non issues if properly encased. Crazy idea: turn road stripes into magnetic tape, encode the data and read it like a tape player :P
- tuukkah 8y agoRegarding #4, I know RFID chips and readers are used for positioning in the Helsinki subway, but I don't know if they have some kind of special antennas allowed by the tracks and the long cars.
- Fnoord 8y agoPossibly also Eurobalise? [1] The Berlin S-Bahn's ZBS (basically "tram") also uses it. But the U-Bahn ("metro") isn't mentioned, and no metro system is mentioned on that Wikipedia page. So I suppose it is some kind off underground variant? [1] https://news.ycombinator.com/item?id=17548552 https://news.ycombinator.com/item?id=17548552
- tuukkah 8y agoI don't know if Eurobalise is based on RFID. Here's some more public info on the Helsinki RFID case: "rugged, intelligent and innovative turnkey solutions for railroad infrastructure providers and train operators based on passive Gen2 RFID technology." https://turckvilant.com/success_story/helsinki-metro/ https://turckvilant.com/success_story/helsinki-metro/ And here's a reverse system where the track identifies the passing wagons: https://turckvilant.com/success_story/running-at-250km-h/ https://turckvilant.com/success_story/running-at-250km-h/
- kalleboo 8y agoRe: #4, this type of technology is already in use for trains and works at speeds of up to 500 km/h. Of course those are always perfectly aligned. https://en.m.wikipedia.org/wiki/Eurobalise https://en.m.wikipedia.org/wiki/Eurobalise
- Kadin 8y agoVery cool -- I was not aware of this. It's interesting that RFID developed out of, partly, a desire by freight train operators to track traincars as they moved around switching yards (moving past fixed readers). The Eurobalise system is sort of the reciprocal of that idea.
- nine_k 8y agoDefinitely just throwing RFIDs into the asphalt would be inefficient. They could instead be mounted on the lane-separation poles / walls, on the cat-eye embedded marks, and other things that are installed on the road anyway, and have a good protection and line-of-sight.
- Kadin 8y agoPutting an RFID chip into the lane reflectors / raised pavement markers seems like it would be a good step, and could be useful both to autonomous systems and driver-assist / navigation systems. I doubt it would add a significant percentage to their cost. The nice thing is that you really don't need to use any intelligence when placing the markers. They could be permanently set with a random GUID at time of manufacture, and then just installed in the road. After installation, someone (e.g. Google Maps car or crowdsourced project) could drive the road and cross-reference the RFID GUIDs to their actual location.