How to calculate RSSI and Distance

[vishal]

Hi
     I am working in a mesh network..I need to calculate the RSSI and distance to localise an end device.I  read the register value in the device to know the RSSI.Form this how can I convert it into RSSI in dBm and how this RSSI can be used to determine the  x,y coordinate to locate a device.I read about the triangulation method.its not applicable here..Taking 3 points is difficult.Can you specfy a method for calculating the same.

[ataradov]

There is no correlation between distance and RSSI that will let you determine the location with any sort of accuracy.

There are solution that are RSSI based, but they mostly suck, and require very careful antenna design.

Why do you think that triangulation will not work? Measure RSSI to/from 3 other devices and some simple algebra will let you know relative position of the device in relation to the other 3. This assumes complete lack of noise and totally onmidirectional antennas, which never happens in real life.

[tggzzz]

Hi
     I am working in a mesh network..I need to calculate the RSSI and distance to localise an end device.I  read the register value in the device to know the RSSI.Form this how can I convert it into RSSI in dBm and how this RSSI can be used to determine the  x,y coordinate to locate a device.I read about the triangulation method.its not applicable here..Taking 3 points is difficult.Can you specfy a method for calculating the same.

Not possible. The randomness of the radio propagation channel prevents it. Initial search terms: "multipath propagation" and "fresnel zone".

Be grateful for multipath propagation; if it didn't exist, neither would cellphones and WLANs.