Is it possible to determine the distance to a Bluetooth device? or to a Wi-Fi device?

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Akson872012-02-07 04:41:01

Android

Akson87, 2012-02-07 04:41:01

Actually the question is, is it possible to determine the distance to the device connected via bluetooth with more or less reasonable accuracy (10-50cm)? For example, do it on a smartphone under Android.
And immediately the same question about Wi-Fi.

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4 answer(s)

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petushok, 2012-02-07
@petushok

Bluetooth: no. Here is the proof: bit.ly/xzBBTX.
Wifi: yes, but with little accuracy. bit.ly/A7wsMk

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sergeypid, 2012-02-07
@sergeypid

What a sly

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anmipo, 2012-02-07
@anmipo

Using only the strength of the received radio signal, an accuracy of 0.1–0.5 m cannot be obtained. Different ways of holding the phone in hand, and whether the user is between devices, significantly affect the received signal.
Graphs can be viewed here: " Accurate Extraction of Face-to-Face Proximity Using
Smartphones and Bluetooth " [pdf]. Wi-Fi will be about the same.
Alternatively, beeps can be used. Microsoft Research Asia claims centimeter accuracy (" BeepBeep: A High Accuracy Acoustic Ranging System using COTS Mobile Devices " [pdf]).

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Mikhail Rozhkov, 2012-02-08
@shogunkub

At the distance you want - it is impossible to properly measure distances by BT or Wi-Fi signal strength. The fact is that up to approximately 10 wavelengths (For 2.4 GHz, this turns out to be somewhere around 1.25m, if I counted correctly) - the Fresnel zone for the antenna. In the near zone, the signal level is not proportional to the distance to the antenna, but changes sharply from minimum to maximum (in the case of light, it will look like Fresnel rings). So alas, the laws of physics are against you...