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Comment by olefoo | Hacker News Reader

With two or more beacons in range you can triangulate for an accuracy within centimeters. It's a key enabling technology for Augmented Reality. It's also how you're going to talk to ambient environmental controls and retrofit older buildings with situational awareness (thalience) that allows them to be responsive to the needs of humans passing through.

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Do you have any examples of this? I was excited for this use but everything I can see suggests that it is highly inaccurate:

https://stackoverflow.com/questions/20332856/triangulate-exa...

This is why it's bleeding edge technology. At the moment it's not very good; and it won't be for some time. To get to something useful will probably take multiple iterations.

This is why it's so exciting. If you can build something useful with the current generation of technology; it will get better.

But you said:

"With two or more beacons in range you can triangulate for an accuracy within centimeters."

it appears that is objectively not true. In fact, the technology powering iBeacons does not seem to be capable of it. So, sure, in a few year's time, a beacon-like technology that may or may not be called iBeacons will allow for accurate positioning. So what?

I've seen a demo; it was finicky and had issues and didn't do orientation.

BLE is not ideal for accurate positioning, or RSSI for that matter. That said, it works for proximity, which should be sufficient for many applications.

iBeacon doesn't give you anything useful for triangulation. Sorry. A closer beacon can give you worse signal than the one which is far. That's the nature of Blutooth.

*>> A closer beacon can give you worse signal than the one which is far.

Well, the calibration helps quite a bit.

I'm not 100% on-board with the triangulation either.

But for proximity (with the calibration), I think it is repeatable to within inches.

It still depends on the environment. If you've got any kind of obstacles, those will affect the signal strength. If a metal shelf or the bag of water I call a body is between me and a beacon, it may think I'm further away than if my phone has a direct line of sight down an aisle to the beacon. Unless you can control for all that, it's not going to be very reliable at all.

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