A Valid Comparison of Vector and Scalar Tracking Loops

This paper analyzes the benefits offered by vector tracking loops relative to scalar tracking loops. A method for designing equivalent scalar and vector tracking loops is first introduced. The benefits of vector tracking are then determined by comparing the two equivalent algorithms. The improvements in signal tracking afforded by vector tracking are quantified in different scenarios using covariance analysis and Monte Carlo simulations. The vector tracking algorithms show a maximum improvement in tracking threshold of 6.2 dB with an eleven satellite constellation and a minimum improvement of 2.4 dB with a five satellite constellation. The results presented in this paper demonstrate the amount of improvement vector tracking can provide in different situations. Furthermore, the analysis technique used to design the equivalent tracking loops provides a simple way to compare other attributes of the algorithms, such as their multipath immunity and robustness.