protected static double calculateDistance(int txPower, double rssi)
{
if (rssi == 0)
{
return(-1.0); // if we cannot determine distance, return -1.
}
double ratio = rssi * 1.0 / txPower;
if (ratio < 1.0)
{
return(Math.Pow(ratio, 10));
}
else
{
double accuracy = (0.89976) * Math.Pow(ratio, 7.7095) + 0.111;
return(accuracy);
}
}