MAESTRO: Understanding Multipath - Antenna - Receiver Interactions for Standardizable Calibration of Code Phase Variations of GNSS Receiving Antennas

• Applicants: Dr. Stefano Caizzone; Professor Dr.-Ing. Steffen Schön
• Subject Area: Geodesy, Photogrammetry, Remote Sensing, Geoinformatics, Cartography ; Communication Technology and Networks, High-Frequency Technology and Photonic Systems, Signal Processing and Machine Learning for Information Technology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 470510446

One of the most challenging open research questions in positioning with Global Navigation Satellite Systems (GNSS) is how to precisely characterize the hardware used for the measurements. Antennas are the first block of the GNSS receiving chain and have an important role in the overall error budget. In more and more applications, such as time transfer, aeronautics or precise point positioning (PPP), the obtainable quality relies on accurate antenna characterization and need precise information about the code-related antenna errors. While precise calibration strategies have been developed in the carrier phase domain, the characterization of the code phase variations (CPV) is still challenging because of higher noise and more severe multipath, and a sufficient understanding of the antenna - receiver - multipath interactions is missing, especially in the geodetic community.Combining the background from geodesy (IfE) and electrical engineering (DLR), this project will close this knowledge gap and gain fundamental physical insights in antenna - receiver - multipath interactions to establish novel methods for consistent CPV calibration. This will be achieved through two complementary strategies, pushing the CPV accuracy level to standardization requirements. DLR will use the know-how about multipath characterization and antenna design to develop a new strategy using an ad-hoc reconfigurable antenna as multipath probe able to fully characterize the multipath environment on the rooftop where the IfE robot is placed. As a result, a code multipath error map is derived, that characterizes the multipath - antenna interaction. IfE will analyse the role of the GNSS receiver during the antenna calibration and subsequently develop a new robot calibration strategy for CPV with reduced pseudorange noise and improved stability of the CPV estimation. This will be done by integrating adequate countermeasures like multipath information retrieved by DLR and the optimization of the receiver settings. The obtained improvements will then be compared with calibration results coming from the anechoic chamber at DLR. The gained know-how about antenna CPV and its interaction with receiver and multipath is of great interest for the scientific community. We will use it to analyze the improvements when applying the new CPV in aeronautics, timing and PPP applications and to derive general antenna installation guidelines.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Tobias Kersten