Patent ID: 7899126

Claim:
A signal receiver, comprising: a code removal module, removing a pseudo random noise code from a first signal to obtain a second signal; a carrier removal module, coupled to the code removal module, generating a carrier signal with a frequency of an estimated carrier frequency, generating at least one delta carrier signal with a frequency of the estimated carrier frequency plus a delta frequency, removing the carrier signal from the second signal to obtain a third signal, and removing the delta carrier signal from the second signal to obtain a fourth signal; a Fast Fourier Transformation (FFT) module, coupled to the carrier removal module, deriving a series of first FFT values from the third signal, and deriving a series of second FFT values from the fourth signal; a signal processor, coupled to the carrier removal module and the FFT module, estimating the carrier frequency of the second signal to obtain the estimated carrier frequency, determining the delta frequency for the carrier removal module, estimating a residual Doppler frequency of the third signal according to both the first FFT values and the second FFT values, and adjusting the estimated carrier frequency according to the residual Doppler frequency to eliminate distortion from residual Doppler effects from the third signal; wherein the delta frequency is lower than a frequency resolution of the FFT module.