Patent ID: 6658048
Filing Date: 2003-12-02
Classification: G01S,H04B

Abstract:
A method of reducing the effects of multipath signal components associated with a received direct path signal comprising a carrier frequency that is modulated by a repetitive pseudo-random noise (PRN) code having M chips of code length, where M is a positive integer, comprising the steps of:demodulating the receive signal to obtain the PRN code; generating a replica code corresponding to the pseudo-random noise (PRN) code of the received signal; delaying the generated replica code for at least first, second and third different delay times equal in delay distance from each other, where each delay distance is less than one chip; further delaying the replica code for a fourth delay time equal to 1 chip from the second delay time and further delaying the replica code for a fifth delay time equal to more than one chip from the second delay time; correlating each delayed replica code with the demodulated PRN code so as to generate a correlation value for each delayed replica code; adjusting the start time of the replica code generator until the first and third delay time correlation values are substantially equal to each other and are greater than a predetermined value; determining if the correlation values for the fourth and fifth delay times are substantially equal to each other and if the fourth and fifth correlation values are not substantially equal to each other, adjusting the replica code generator so as to cause the fourth and fifth correlation values to be substantially equal to each other; and; considering the second delay time to be the start of the PRN code.