Locating GSM mobiles using antenna array

The authors consider the problem of accurate estimation of the position of a GSM mobile station based on measurements of the mobile signal made at a single receiving site equipped with an antenna array. Direction of arrival and time of arrival measurements are used to estimate the location of the mobile transmitter. A statistical filtering technique is applied to the location estimates to minimise the effects of multipath fading. Experimental results with a DCS-1800 system are presented which achieve an r.m.s. location error of 133 m, with the error being <250 m for 98% of the time