A New Asymmetric Correlation Kernel for GNSS Multipath Mitigation

Multipath is the dominant error source in precise positioning Global Navigation Satellite Systems (GNSS) such as the United States Global Positioning System (GPS). These systems utilize the satellite signal time of arrival estimates to solve for position. Multipath corrupts the time of arrival estimates by distorting the signal tracking phase discriminator; which results in a slowly time- varying phase bias. This bias ranges from several centimeters to tens of meters. The submeter bias is the most problematic for centimeter positioning systems. Moreover, in addition to multipath, the GPS spread spectrum code is unbalanced for certain space vehicles which can lead to a code tracking phase bias. A new correlation kernel is proposed as part of a multipath mitigating delay-locked- loop code phase discriminator that does not suffer a tracking bias due to unbalanced spreading codes. This new algorithm performance is compared to existing techniques with respect to position bias and robustness.