A METHOD OF DESPREADING GPS SPREAD SPECTRUM SIGNALS, A BASE STATION FOR PROVIDING ASSISTANCE TO A MOBILE UNIT FOR DESPREADING GPS SPREAD SPECTRUM SIGNALS, AND A MOBILE UNIT FOR DESPREADING A GPS SPREAD SPECTRUM SIGNALS

摘要

A method of despreading a GPS spread spectrum signal received at a mobile unit MS1 with assistance from a base station BS1 is disclosed comprising the steps of (a) receiving and despreading GPS signals at the base station and deriving GPS signal information therefrom; (b) estimating the location of the mobile unit; (c) modifying the GPS signal information so as reflect the GPS signal characteristics as would be observed at the estimated location of the mobile unit; (d) transmitting the GPS signal information from the base station to the mobile unit; (e) generating replica signals containing PRN codes corresponding to those of the GPS signal using the modified GPS signal information; and (f) performing a correlation of the GPS signal and the replica signals in order to acquire the GPS signal.