| 摘要 |
PURPOSE: An user positioning system is provided, which can improve a pseudo distance measurement accuracy and can realize a strong satellite signal tracking part. CONSTITUTION: According to a correlator enabling a navigation data processor part to track a satellite signal using a correlation value between a code transferred from a satellite and a self-generated code, a carrier NCO(Numerically Controlled Oscillator)(22) generates sine waves corresponding to I and Q respectively. The first and the second carrier mixer(24,26) offsets a doppler by multiplying an intermediate frequency by the sine wave corresponding to I and the sine wave corresponding to Q being output from the carrier NCO. A code NCO(28) generates a basic frequency to generate a PRN(Pseudo Random Noise) code according to a satellite signal tracking error provided from the navigation data processor part. A code phase counter(30) calculates a phase for a unit time by receiving a frequency provided from the code NCO and then provides it to the navigation data processor part. A code generator(32) generates a PRN code of the satellite by receiving the frequency from the code NCO. The first code mixers(38-46) and integrators(48-56) multiply an output of the first carrier mixer and each code from the code generator and then integrate them and calculate a correlation value, and then provide it to the navigation data processor part. And the second code mixers(58-66) and integrators(68-76) multiply an output of the second carrier mixer and each code from the code generator and then integrate them and calculate a correlation value, and then provide it to the navigation data processor part. The above correlation value is calculated using a narrow chip spacing correlator and a wide chip spacing correlator at the same time. |
