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I am developing a app for Bluetooth device.

I used iBeacon feature for indoor location, but can't find indoor location, it return only region.

I have a current location. But now I want to find distance between current location to iBeacon location. I searched a lot. But didn't get any proper solution.

From my search I get to know that I can find distance from RSSI.

But my question is how can I find location or distance with that property.

halfer
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Er.Shreyansh Shah
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  • do you want to find location in longitude latitude of iBeacon, or range in meters for example? – l0gg3r Jan 13 '15 at 10:25
  • possible duplicate of [Finding distance from RSSI value of Bluetooth Low Energy enabled device](http://stackoverflow.com/questions/13705647/finding-distance-from-rssi-value-of-bluetooth-low-energy-enabled-device) – Raptor Jan 13 '15 at 10:28
  • If we can find in latitude and longitude than good. If it returns in meter than how can i convert it to latitude and longitude. – Er.Shreyansh Shah Jan 13 '15 at 10:29

2 Answers2

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You can't find current position (in longitude latitude) by using 1 iBeacon, But if you want to find distance (for example beacon is in range of 5 meters) than look this document. The formula is #19 on page 3 and basically it is this:

Received Signal Strength is related to distance using the
equation below.
RSSI [dBm] = -10n log10 (d) + A [dBm]

Where
A is the received signal strength in dBm at 1 meter - you need to calibrate this on your system. Because you are calibrating at a known distance you don't need to take into account the frequency of your transmission and this simplifies the equation. (Just place the iBeacon to 1 meters range, and measure it's RSSI)

n is the propagation pathloss exponent i.e. 2.7 to 4.3 (Free space has n = 2 for reference, if there are walls it will be greater).

d is the distance from the sender in meters

So you have all values, except d, you need to calculate d by using mentioned formula.

BTW, if you want to get position of beacon, you need to triangulate it (by using more than 3 beacons) look here

Community
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l0gg3r
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0

CLBeacon class has a property named accuracy for it. Apple Developer Site Reference

ondermerol
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