# Virtual Validation of In-Flight GNSS Signal Reception during Jamming for Aeronautics Applications
###### Abstract  
Accurate navigation is a crucial asset for safe aviation operation. The GNSS (Global Navigation Satellite System) is set to play an always more important role in aviation but needs to cope with the risk of interference, possibly causing signal disruption and loss of navigation capability. It is crucial, therefore, to evaluate the impact of interference events on the GNSS system on board an aircraft, in order to plan countermeasures. This is currently obtained through expensive and time-consuming flight measurement campaigns. This paper shows on the other hand, a method developed to create a virtual digital twin, capable of reconstructing the entire flight scenario (including flight dynamics, actual antenna, and impact of installation on aircraft) and predicting the signal and interference reception at airborne level, with clear benefits in terms of reproducibility and easiness. Through simulations that incorporate jamming scenarios or any other interference scenarios, the effectiveness of the aircraft's satellite navigation capability in the real environment can be evaluated, providing valuable insights for informed decision-making and system enhancement. By extension, the method shown can provide the ability to predict real-life outcomes even without the need for actual flight, enabling the analysis of different antenna-aircraft configurations in a specific interference scenario.  
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to eventual jamming events, even without flying, with clear benefits in terms of finance and effort. Multiantenna systems are known to be powerful countermeasures and have been vastly investigated in the latest years [9; 10; 11; 12; 13]. The authors have also proposed miniaturized antennas, capable of fitting into avionic footprints for single antenna elements, for optimal compliance with legacy systems [14; 15]. In order to better study the flight behavior of these antennas, our institute in the German Aerospace Center (DLR) is performing a series of flight measurement campaigns at its Cochstedt site: the first one was performed in 2022, and then in 2023 and more shall follow in 2024. The results recorded with the single antennas of the DLR array (whose design was shown in [15]), will be used in this paper as a reference. Please note that the combined use of the antennas, such as to produce interference suppression, is not part of this work and will be the focus of a different paper. The focus of this paper on the other hand is to show the capability to predict the in-flight performance by a virtual validation tool.  
In the literature, several authors have shown EM simulation tools for simulating the installed performance of the antenna on platforms/aircraft [16; 17; 18], but to our best knowledge, no work is publicly available showing the flying performance. In this article, we discuss the predictive tool that can well approximate beforehand the performance that will be obtained later on in-flight. Then we validate the simulation data with the data collected during flight trials that involve GNSS reception in the presence of jammer. This approach helps engineers predict the performance of antennas in challenging environments, enabling them to take proactive measures in advance without having to spend time and money on expensive flight tests.  
This article consists of five sections. The introduction is provided in Section 1. Section 2 provides the details about DLR's measurement campaign whose data will be taken as a reference for the virtual validation. Installed performance analysis of the receiver antenna/jammer over aircraft/ground is explained in Section 3. Section 4 covers full-scenario simulation with two scenarios: (1) Jamming power level estimation, and (2) GNSS reception during jamming. Simulation and measurement results are discussed in Section 1. Finally, conclusions are given in Section 5.