Patent ID: 6389264
Filing Date: 2002-05-14
Classification: G01S,H04W

Abstract:
A method to estimate the distance of a mobile to a transceiver in a timing advanced controlled system having a timing advance, said method comprising the steps of:(a) determining if timing advance change criteria are satisfied when a signal from the mobile is delayed by a delay at the transceiver; (b) adding a first stepsize to said delay if the timing advance change criteria are not satisfied, the first stepsize having a time period less than that of the timing advance, and repeating steps (a) and (b) with said delay used in step (a) increasing, as last incremented in step (b), until said timing advance change criteria are determined to be satisfied; (c) subtracting, in response to a determination that said timing advance change criteria are satisfied, the first stepsize from said delay and adding a second stepsize to said delay and adding a second stepsize to said delay; (d) determining if said timing advance change criteria are satisfied when a signal from the mobile is delayed by said delay at the transceiver; (e) adding a second stepsize to said delay if the timing advance change criteria are not satisfied, the second stepsize having a time period less than that of the first stepsize, and repeating steps (d) and (e) with said delay used in step (d) increasing, as last incremented in step (e), until a determination in step (d) that said timing advance change criteria are satisfied; and (f) calculating, in response to a determination in step (d) that said timing advance change criteria are satisfied, the distance based on said delay as last incremented in step (e).