[Tinyos-help] Distance Estimation by RSSI

[VINITA DAIYA]

Hello Sir
I am doing project on "Distance Estimation By RSSI"
In my project i am using IRIS motes. When I am reading the
PHY_RSSI(0x06) register for Rssi value as per AT86RF230 datasheet its
giving always a constant value( not varying with distance). After
reading tinyos help I read ED_LEVL(0x05) Register Its value is the
averaged RSSI over six samples. Its value is varying with distance but
Sir I am not able to get how to establish a approx relation with
distance using ED value.

How to convert this ED value to dBm ? Can I do just by subtracting 91
from each value. As in datasheet giveen 0 value corresponds to  -91dBm

Thank You
BARC Training SCHOOL
Trainee