Multi-Frequency Vector Tracking GNSS Receiver with Ionosphere Estimation

Position, velocity, and time (PVT) information is essential for a variety of applications. Global navigation satellite systems (GNSSs) are widely used for this purpose due to their global availability. However, the nearer receiver environment as well as atmospheric effects, especially from the ionosphere, can have a large impact on their performance. A proven approach to address the first is the use of vector tracking (VT) receiver architectures. They are known to be more robust in challenging environments such as dense urban areas. For the latter, multi-frequency receivers allow for a direct observation of the frequency dependent delays. In contrast to the use of conventional ionospheric models, this approach has the potential to accurately eliminate this effect. Moreover, it does not underlay regional restrictions like more accurate ionospheric corrections from Satellite Based Augmentation Systems (SBASs). To cope with both challenges at the same time, we propose a multi-frequency VT receiver architecture with ionosphere estimation. The capabilities of the proposed solution are demonstrated using a GNSS constellation simulator and actual measurements from the publicly available TEX-CUP data set and compared, among others, against a VT variant that relies on ionospheric modeling.