Current standardization activities in the aeronautical community are paving the way to using multifrequency multiconstellation GNSS as a primary means of aircraft navigation. The increase in the number of satellites from different constellations as well as the increasing use of multiple frequency GNSS receivers promise improvements in the achievable accuracy in GNSS positioning. The effects of receiver antennas shall be investigated because of the stronger impact of possible imperfections on the overall error budget for multifrequency combinations. The scope of this paper is to show the possibility of properly modeling and indeed characterizing the antenna‐induced GNSS pseudorange errors, through simulations and electromagnetic measurement. An insight into antenna characteristics giving rise to such errors will be given, by analyzing the impact of the feeding technique on the achievable pattern uniformity and hence on antenna‐related pseudorange errors. The technique is then validated through GNSS field measurement.

Satellite navigation is more and more important in a plethora of very different application fields, ranging from bank transactions to shipping, from autonomous driving to aerial applications, such as commercial avionics as well as unmanned aerial vehicles (UAVs). In very precise positioning, navigation, and timing (PNT) applications, such as in reference stations and precise timing stations, it is important to characterize all errors present in the system in order to account possibly for them or calibrate them out. Antennas play an important role in this respect: they are indeed the “sensor” that capture the signal in space from global navigation satellite systems (GNSS) and thereby strongly contribute to the overall achievable performance. This paper reviews the currently available antenna technologies, targeting specifically reference stations as well as precise GNSS antennas for space applications, and, after introducing performance indicators, summarizes the currently achievable performance. Finally, open research issues are identified, and possible approaches to solve them are discussed.

In this work an overview of numerous possible processing modes in future dual frequency, dual constellation GBAS is given and compared to the current GAST D standard. We discuss the individual error contributions to GBAS protection levels and give an overview of the general processing. Based on this the consequences when adding a second constellation as well as frequency are investigated. Geometrical implications and changes to the residual differential error bounds are studied separately first. In terms of geometry a comparison between the single and dual constellation case is presented using dilution of precision as metric. The influence on the different sigma contributions when using new satellites (Galileo) and signals (E1, L5, and E5a) is individually discussed based on recent measurements. Final simulations for different varying parameters are carried out to compare relevant processing modes in terms of achieved nominal protection levels. A concluding discussion compares the outcomes and analyzes the implications of choosing one or the other mode.

The Ground Based Augmentation System (GBAS) is a landing system for aircraft based on differential corrections for the signals of Global Navigation Satellite Systems (GNSS), such as GPS or Galileo. The main impact on the availability of current single frequency systems results from the necessary protection against ionospheric gradients. With the introduction of Galileo and the latest generation of GPS satellites, a second frequency is available for aeronautical navigation. Dual frequency methods allow forming of ionospheric free combinations of the signals, eliminating a large part of the ionospheric threats to GBAS. However, the combination of several signals increases the noise in the position solution and in the calculation of error bounds. We, therefore, developed a method to base positioning algorithms on single frequency measurements and use the second frequency only for monitoring purposes. In this paper, we describe a detailed derivation of the monitoring scheme and discuss its implications for the use in an aviation context.

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.

Satellite navigation is more and more important in a plethora of very different application fields, ranging from bank transactions to shipping, from autonomous driving to aerial applications, such as avionics as well as unmanned aerial vehicles (UAVs). Due to the increasing dependency on satellite navigation, the need for robust systems able to counteract unintentional or intentional interferences is growing. When considering interference-robust designs; however, the complexity increases. Top performance is obtained through the use of multi-antenna receivers capable of performing spatial nulling in the direction of the interference signals. In particular, mobile applications (aeronautics, UAVs, automotive) have a substantial interest in robust navigation, but they also have the strongest constraints on the weight and available places for installation, with the use of bigger and heavier systems posing a substantial problem. In order to overcome this limitation, the present work shows a miniaturized five element (4+1) antenna array, which operates at the L1/E1 band (with array capability), as well as at the L5/E5 band (as a single antenna). The proposed antenna array is able to fit into a 3.5-inch footprint, i.e., is compliant with the most widespread footprints for single antennas. Moreover, it is capable of multiband operation and meets the requirements of dual-frequency multi-constellation (DFMC) systems. Thanks to its extreme miniaturization and its compliance with current airborne single antenna footprints, the presented antenna array is suitable for easy integration in future aerial platforms, while enabling robustness and enhancing interference mitigation techniques using multi-antenna processing.