CODE TRACKING LOOP AND METHOD FOR MULTIPATH ERROR MITIGATION

摘要

A code tracking loop for removing a multi-path error and a multi-path error removing method are provided to decrease dissymmetry by tracking dissymmetry of a correlation function by using two correlators and then deciding a correction value. A code tracking loop for removing a multi-path error is composed of a first correlator generating each correlation value by multiplying and integrating an input signal of a receiver and an early code signal of a first signal generated from a code generator, and the input signal and a late code signal of the first signal; a second correlator(702) generating each correlation value by multiplying and integrating the input signal of the receiver and an early code signal of a second signal generated from the code generator, and the input signal and a late code signal of the second signal; a phase discriminator(710) detecting a phase error by using the correlation values generated from the first or second correlator; a loop filter(712) removing noise of the phase error calculated by the phase discriminator; a code DCO(Digitally Controlled Oscillator,714) outputting a control signal for compensating phase error by using the phase error separated from the noise in the loop filter; a code phase counter(704) measuring a first pseudo range of the first signal or a second pseudo range of the second signal generated from the code generator by using the control signal generated from the code DCO; a correction value generating unit(706) comparing the first and second pseudo ranges measured by the code phase counter and generating a correction value by using the difference between the pseudo ranges; and a correlation function dissymmetry correcting phase discriminator(708) measuring a phase error for the first signal by reflecting the correction value generated from the correction value generating unit to the correlation value of the late code signal of the first signal.