nrf51 dongle calculate distance

[adrian_ng]

hi

I used the nrf51 dongle to receive advertisement packet from other nrf51 dongle. I used this formule, d = 10 ^ ((TxPower - RSSI) / 20) , given from this link forums.estimote.com/.../2858 .

Example, txpower = -59, and received rssi is -80. d = 10 ^ ((21) / 20) = 11.2m

However, even the distance in between the two dongles are around 1m, it display very weird distance value like 10-20m. Is it the calculation method wrong? or is the antenna poor performance?

[awneil]

Unless everything is very carefully calibrated & controlled, RSSI can only give a very rough estimate of distance at best.

You can really only expect a near/far indication.

[awneil]

The post you referred to actually makes this clear:

This will give you very "jumping" results, coming from the nature of RSSI. RSSI readings are not very stable and highly depend on environment