Abstract: The estimation of local mean signal strength is the core of SSOA (Signal Strength Of Arrival) location. The primary source of error is fast fading and shadowing (slow fading). Signal strength averaging is an important approach to estimate the local mean. This paper suggests a double-averaging algorithm with dynamic widow-width to improve the estimation and thus enhances the location accuracy. The results of computer simulation proved that the methods improve location accuracy by 30% than traditional methods in fading channel. And, with the aid of dynamic window-width, sufficient location accuracy can be obtained while mobile station is in low mobility.