Patent ID: 8116789

Claim:
A method of estimating the location of a mobile terminal in a mobile communications network having a plurality of base stations, the method including: determining at least one signal parameter measurement for the mobile terminal in relation to each of the plurality of base stations; using the determined signal parameter measurements to obtain a first distance estimation of the mobile terminal from each of the plurality of base stations; and using at least one estimator on each of the first distance estimations to obtain a refined distance estimation of the mobile terminal from each of the plurality of base stations, the plurality being the number i, the estimator conforming to a format selected from the following: d ^ 1 ⁡ ( i ) = c 1 ⁡ ( i ) · d ^ ( i ) = - ⅇ - β ⁡ ( i ) ⁢ σ Rx 2 2 · d ^ ⁡ ( i ) = ⅇ - β ⁡ ( i ) ⁢ σ Rx 2 2 · 10 R ^ x ⁡ ( i ) + A ⁡ ( i ) B ⁡ ( i ) a ) d ^ 2 ⁡ ( i ) = ⅇ - β ⁡ ( i ) ⁣ · 3 ⁢ σ Rx 2 2 · 10 - R ^ x ⁡ ( i ) + A ⁡ ( i ) B ⁡ ( i ) b ) {circumflex over (d)} 3 ( i )= c 3 ( i )· {circumflex over (d)} ( i ), with c 3 ( i )= e −β (i) σ RX 2 c) {circumflex over (d)} 4 ( i )= c 4 ( i )·{circumflex over ( d )}( i ), with c 4 ( i )= e −3β (i)· σ Rx 2 d) where: i=1, 2, 3, σ Rx 2 is the variance of a Received Signal Strength (RSS) Gaussian distribution, β(i)=(ln(10)/B(i)) 2 , B(i)=44.9−6.55 log h bs (i), h bs (i) is the height of Base Station (i) in meters, A(i) is an estimation of a propagation path-loss quantity from Base Station (i), R x (i) is the measured RSS from Base Station (i) in dbm at the terminals actual location; and using said plurality of refined distance estimators to obtain a positional estimation of the mobile terminal.