Differential vector phase locked loop

Abstract

A novel differential vector phase locked loop (DVPLL) is derived that takes global navigation satellite system (GNSS) code-phase and carrier-phase measurements from a base station and uses them to maintain a position with centimeter-level accuracy directly in the vector tracking loop of a rover receiver. The navigation filter uses five state variables, three position and two clock states, to create the replica code and carrier measurements for a static test. There are no individual channel states or feedback mechanisms. Closing the individual loops solely through the navigation filter makes this a purely vector method. For short baselines, where differential atmospheric errors are small, the DVPLL can be used on single-frequency data. An L1-only live-sky static test was performed using the method, resulting in a three-dimensional accuracy of 1.3 mm for a zero-baseline and 5.3 mm for an 18.5 m baseline.