On the path to precise geodetic levelling with low-cost GNSS antennas

Abstract Low-cost GNSS antennas have enabled a wide range of new applications where traditional GNSS equipment is associated with substantial financial cost. However, low-cost equipment also has a serious drawback: low-cost GNSS antennas are typically characterized by high susceptibility to multipath, poorly known or unavailable PCO/PCV calibrations, and large inter-antenna PCV variability even among antennas of the same model, which significantly limits their performance in high-precision applications. The goal of this study is to verify whether, with the low-cost GNSS antennas, it is feasible to provide precise ellipsoidal heights, that is, an intermediate step in GNSS geodetic levelling. In this way, we address a scientific question on the potential usability of low-cost antennas for precise normal height determination in geodetic and surveying applications. We pay particular attention to the impact of antenna phase center characteristics on height determination with GNSS. In this regard, we apply, for the first time, a web service-derived PCC to obtain more accurate antenna phase patterns of low-cost antennas. The usability of these patterns is examined, and the results are validated against those obtained with high-grade GNSS antennas. We demonstrated that low-cost antennas can achieve ellipsoidal heights with accuracy comparable to that of high-grade antennas. Finally, we show that applying web-based calibrations may enhance the accuracy of the GNSS height determinations using mass-market GNSS antennas.