Patent ID: 6345068
Filing Date: 2002-02-05
Classification: G01S,H04B

Abstract:
A method for tracking an incoming signal including a plurality of chips of a certain chip duration, comprising the steps of:(a) generating a plurality of instances of a code, said instances being ordered hierarchically, one of said instances being a first instance, such that for each of said instances other than said first instance, there is a preceding instance; (b) for each of said instances, correlating the incoming signal with said code to produce an early correlation and a late correlation, said early correlation being advanced in time relative to said late correlation by a certain multiple of the chip duration, such that, for each of said instances other than said first instance, said multiple is less than said multiple associated with said preceding instance, thereby producing a control signal representative of a timing mismatch between the incoming signal and said code; (c) for each of said instances, transforming said control signal into a code phase signal that is a function of a respective said multiple of the chip duration, said code phase signal of each of said instances other than said first instance being adjusted based both on said control signal and on said code phase signal of said preceding instance; and (d) transforming said code phase signals into a combined code phase signal by extrapolating said code phase signals to zero said multiple of the chip duration.