A Review of GPS Cross Correlation Mitigation Techniques
Éamonn P. Glennon, Andrew Graham Dempster, Éamonn P. Glennon · 2004
Detection of weak GPS signals is becoming important in many applications of GPS, including E911 positioning and the secondary use of GPS signals for remote sensing applications. Cross correlations caused by the limited dynamic range of GPS Gold Codes represent a significant problem in the observation of weak GPS signals. This paper presents a brief analysis of the cross correlation problem followed by a review of the various cross correlation mitigation techniques that are currently available for GPS signal processing, with particular emphasis on cancellation and subspace-projection techniques. Since much of the cross correlation literature is concerned with cross correlations as they relate to CDMA cellular communications, a comparison between GPS and these other CDMA systems is made. The suitability of these techniques to weak signal and ‘indirect-GPS’ applications is discussed, as are the advantages and disadvantages of each method. Applicability of the methods to removal of autocorrelation sidelobes is also examined.