Development of the dual-frequency dual-constellation airborne multipath models

This paper presents a methodology to build multipath models for aviation use of new Global Positioning System (GPS) and Galileo signals. The estimation of airframe multipath errors makes use of 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 is suitable for measurements from flight data and is able to exclude measurements highly affected by multipath from the estimation by using a derived standard deviation based on the receiver thermal noise only. Next, an overview of 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 proposed. Finally, the paper discusses overbounding of the observed multipath errors to safely bound the tail risks and the inflation needed to account for uncertainty due to limited amounts of data.