1. A system for determining the location of a mobile radio station relative to radio base stations, comprising a plurality of radio base stations, each equipped to transmit a signal; and a mobile radio station equipped to receive the signal transmitted by each radio base station and having means for estimating the time of arrival of each received signal and means for computing the location of the mobile radio station from the estimated time of arrival of each received signal, wherein the means for estimating the time of arrival further comprises a means for making a first estimate of time of arrival having a first resolution and a means for making a second estimate of time of arrival having a second resolution, the first estimate of time of arrival contributing to defining the scope of the means for making the second estimate of time of arrival, and the second resolution being more refined than the first resolution.