  This paper considers the localization problem in a 5G-aided global navigation
satellite system (GNSS) based on real-time kinematic (RTK) technique.
Specifically, the user's position is estimated based on the hybrid
measurements, including GNSS pseudo-ranges, GNSS carrier phases, 5G
angle-of-departures, and 5G channel delays. The underlying estimation problem
is solved by steps that comprise obtaining the float solution, ambiguity
resolution, and resolving the fixed solution. The analysis results show that
the involvement of 5G observations can enable localization under
satellite-deprived environments, inclusive of extreme cases with only 2 or 3
visible satellites. Moreover, extensive simulation results reveal that with the
help of 5G observations, the proposed algorithm can significantly reduce the
estimation error of the user's position and increase the success rate of
carrier-phase ambiguity resolution.
