Improved Airborne Multipath Modelling

Mihaela-Simona Circiu, Stefano Caizzone, Michael Felux, Christoph Enneking, Michael Meurer

Abstract:	With the increasing number of satellites broadcasting signals on a second ARNS frequency (L5/E5a) available the dual frequency processing becomes a promising option for the next generation aviation users. In this context, characterizing the error sources of the navigation solution is crucial. This evaluation is particularly important because the next generation aviation users of GNSS will be able to utilize dual frequency measurements and eliminate the previously dominant ionospheric error term from the user error model. Accordingly, the multipath and code tracking errors will then constitute a much larger relative contribution to the total user ranging error than for a GPS L1 user. It is therefore necessary to carefully analyze the code noise and multipath error distribution to derive appropriate integrity figures for use in SBAS, ARAIM, and GBAS protection level equations. This paper presents the methodology to build the multipath models and proposes several improvements. The estimation of the multipath makes use of the carrier phase measurements, thus it is affected by the integer ambiguities. A new method for removing the ambiguities from the multipath estimation is presented. The method suitable for measurements from flight data and is able to exclude measurements highly affected by multipath by using a derived ???? based on the receiver thermal noise only. Next, an overview on the error sources relevant for the multipath estimation is given and a first concept to separate the receiver antenna errors from the multipath errors is presented.
Published in:	Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018) September 24 - 28, 2018 Hyatt Regency Miami Miami, Florida
Pages:	2195 - 2209
Cite this article:	Circiu, Mihaela-Simona, Caizzone, Stefano, Felux, Michael, Enneking, Christoph, Meurer, Michael, "Improved Airborne Multipath Modelling," Proceedings of the 31st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2018), Miami, Florida, September 2018, pp. 2195-2209. https://doi.org/10.33012/2018.15855
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