Patent ID: 6067328
Filing Date: 2000-05-23
Classification: G01S

Abstract:
In a Global Positioning System (GPS) receiver including a reference clock, a method of eliminating errors in the code phase measurement of the receiver caused by clock errors of the reference clock, said method comprising the steps of:receiving satellite signals from a GPS satellite;downconverting said received satellite signals with downconverting means for generating downconverted signals;driving said downconverting means with clock signals generated by said reference clock, said reference clock being subject to variations that introduce clock errors to said clock signals and therefore to said downconverted signals;generating replica code signals of said downconverted signals with code generating means;driving said code generating means with oscillator signals generated by oscillator means;comparing said replica signals with said received satellite signals with comparing means, said comparing step being subject to comparison errors associated with said clock errors of said downconverted signals; andeliminating said comparison errors by adding clock correction signals to said oscillator signals for driving said code generating means, said clock correction signals being proportional to said clock errors.