Triangulate using BLE(iBeacons) tags in Android

1
votes

Created a Android application using latest BLE API for indoor positioning.Used the formula found in Triangulate example for iBeacons

But the rssi values from public void onLeScan(BluetoothDevice device, int rssi, byte[] arg2) call back are coming as negative and result of formula is always negative and corrupt values.

How to correct these values?.

I also tried absolute values of the rssi , its giving wrong values.

1
androidiosbluetooth-lowenergytrilateration

1 Answers

3
votes

RSSI(Received signal strength indication) measures are given in dBm. dBm is a logarithmic measure unit so negative values are perfectly valid. Check the wikipedia article about dBm and you will see how to convert them to Watts http://en.wikipedia.org/wiki/DBm It is perfectly explained there.