Method and apparatus for tracking location of user equipment by using integrated GPS and TDOA scheme

A method for tracking a location of a user equipment (UE) by using an integrated Global Positioning System (GPS) and Time Difference Of Arrival (TDOA) scheme in a mobile communication network, the method comprising the steps of:

• obtaining a GPS position solution of the UE by using GPS code information, the GPS position solution being derived using a frequency corresponding to a clock period demultiplied by a chip rate of the mobile communication network;
• obtaining TDOA position solutions by using transmission times of pilot signals transmitted from a plurality of base stations (BSs) and reception times of the pilot signals received at the UE, and calculating an average value of the TDOA position solutions;
• obtaining a corrected position error value by subtracting the GPS position solution from the average of the TDOA position solutions to obtain a position error value, and performing an iterative method using the position error value;
• and
• adding the corrected position error value to the average value of the TDOA position solutions.