This thesis aims to study, implement and validate a realistic 'vector tracking loop' model for GNSS receivers, with the objective of comparing its performance with traditional 'scalar' tracking loops. The analysis is conducted by theoretical and simulation evaluations considering different scenarios. In particular, the robustness of Vector Tracking, i.e., the ability to keep the signal locked, is evaluated in the case of low vehicular dynamics and in the presence of low signal-to-noise ratios, temporary GNSS outages (partial or total). In high vehicular dynamics (with varying values of acceleration), on the other hand, we focused on analyzing what was the maximum tolerable acceleration without changing the order of the loop filter, considering the estimated Doppler frequency and Carrier Phase error and their respective accuracies.