Patent ID: 6772065
Filing Date: 2004-08-03
Classification: G01S,H04B

Abstract:
A GPS receiver, comprising:first fast Fourier transform means for fast-Fourier transforming a received GPS signal having a carrier frequency modulated by transmitted data that is spectrum-diffused by using a diffusion code that is different for each of a plurality of satellites; a diffusion code generator for generating a plurality of said diffusion codes that is different for each signal; a diffusion code adder for adding at least two of the different diffusion codes from among said plurality of diffusion codes generated by said diffusion code generator; second fast Fourier transform means for fast-Fourier transforming an addition result from said diffusion code adder; a multiplier for multiplying a transform result of said first fast Fourier transform means by a complex conjugate of a transform result of said second fast Fourier transform means; inverse fast Fourier transform means for inverse-fast Fourier transforming a multiplication result from said multiplier; a correlation point detector for detecting a correlation point between said GPS signal and at least two of the different diffusion codes in accordance with a transform result from said inverse fast Fourier transform means; and a detector for detecting said carrier frequency of said received GPS signal and said diffusion code used for said spectrum diffusion in accordance with a detection result from said correlation point detector.