Patent ID: 7130332

Claim:
A method for tracking a pilot channel signal to discipline an oscillator, comprising: downconverting an RF signal from a RF center frequency f RF to an intermediate center frequency f L where f L is greater than or equal to a chip rate f c wherein downconverting includes incorporating bandpass filtering to remove extraneous signals while passing said pilot channel signal; converting a signal format from analog to digital using a single analog-to-digital converter employing a sampling rate of f s to create a digital signal {s(n)}; employing a correlation circuit to establish a correlation between {s(n)} and locally generated versions of I-channel and Q-channel PN signals, {I PN (n)} and {Q PN (n)}, respectively; generating an estimate of a frequency error of the oscillator using correlation values corresponding to (2M+1) time shifts of {I PN (n)} and {Q PN (n)}, the (2M+1) time shifts being K−Δ M , K−Δ (M-1) , . . . , K−Δ 2 , K−Δ 1 , K, and K+Δ 1 , K+Δ 2 , . . . , K+Δ (M-1) , K+Δ M , where a time shift of K corresponds to a time shift that provides a maximum correlation value, and M is greater than or equal to 1; and disciplining the oscillator using the estimate of the frequency error of the oscillator, wherein correlation values between the digital signal {s(n)} and at least one locally generated version of I-channel and Q-channel PN signals {I PN (n)} and {Q PN (n)} are averaged over multiple periods of the PN signals to improve a quality of pilot position estimation.