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In a spread-spectrum radio communication system in which transmissions occur with varying amounts of delay and in which the delay of a received signal must be determined in order to despread the signal, a system for refining the initial estimate of delay and for tracking the delay during an ongoing communication by correlating the signal at the estimated delay, an increment earlier than the estimated delay, and the same increment later than the estimated delay, and interpolating the early and late correlations normalized by the correlation at the estimated delay and by the increment to determine a refined estimate of the delay.