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

Abstract

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.

Antennas as Precise Sensors for GNSS Reference Stations and High-Performance PNT Applications on Earth and in Space

“…The antennas were evaluated in terms of C/ (i.e., carrier-to-noise ratio, directly affected by the gain characteristics of the antenna) and 100 s smoothed multipath and noise errors over elevation (calculated through dual-frequency code-minus-carrier methods [ 54 ]). The smoothing is used to reduce the high-frequency noise, allowing a better comparison between the different antennas.…”

Antenna Group Delay Variation Bias Effect on Advanced RAIM

“…Different commercial antennas were measured at DLR and it has been observed that the errors are different for each antenna. For the derivation of the initial AGDV models, the antenna chosen to analyze was the one that had the largest group delay variations for both frequency bands in order to be representative of a minimally MOPS-compliant commercial antenna and provide conservative values at both bands and in the Ifree combination [6]. The same measurements presented in [6] are used in this study.…”

“…Within the Dual Frequency Multipath Model for Aviation (DUFMAN) project funded by European Commission, dual-frequency, dual-constellation (DFDC) airborne multipath models were developed by collecting GPS and Galileo measurements from several test flights using aviation GNSS antenna and receivers [6], [7]. The multipath error models were derived by characterizing the errors introduced by the user antenna biases for the antennas used during the flights and separating their contribution from the observed multipath errors.…”

“…For this purpose, user-satellite geometries are first simulated based on 24 GPS/Galileo constellations and a predefined global user grid formation for ten sidereal days, which corresponds to the repetition period of the Galileo constellation [3]. Next, user AGDV errors in signals propagated to the users are computed based on actual antenna measurements as presented in our previous investigation [9], [10]. In this study, we take two different approaches to the assessment of the AGDV range errors and the new multipath model effect on ARAIM performance: measurement and position domain characterization of the AGDV errors.…”

Network-Based Ionospheric Gradient Monitoring to Support GBAS

“…However, this methodology only applies if the Itest J k distribution is Gaussian. In the case the probability distribution computed with the Itest J k per bin presents a non Gaussian behaviour, we calculate a Gaussian overbound of the tails of the Itest J k distribution per bin following the approach in [16], [17]. Therefore, the detection threshold for station k is defined as:…”