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    Testing of Two-Phase Cooling of Bipolar Plates for Fuel Cells
    (IEEE, 2025) Gerner, H.J. van ; Mühlthaler, G. ; Buntz, M.B.
    Hydrogen-powered fuel cells are the preferred energy source for electric aircraft. However, for aircraft applications, it is of upmost importance to reduce the mass of the fuel cell system. A considerable amount of the total system mass is due to the fuel cell cooling system. This paper discusses two-phase cooling of the bipolar plates in a fuel cell stack. A twostep approach was used. First, test were carried out with machined plates with a geometry similar to bipolar plates. In a second step, actual bipolar plates were tested, including the membranes, seals and gaskets that are present in a fuel cell. These bipolar plates are from a standard fuel cell stack and are intended for water/glycol cooling. The tests show that these standard bipolar plates can be used with two-phase cooling with methanol
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    Interference Detection, Localization, and Mitigation Capabilities of Controlled Reception Pattern Antenna for Aviation
    (MDPI, 2023) Zwol, A. van ; Es, J.J.P. van ; Kappelle, D. ; Zelle, H.D. ; Doctor, F. ; Konter, Y.E.J.
    Global Navigation Satellite System (GNSS) interference poses an increasing threat for civil aviation, and the detection and mitigation of interferences can help to make the sector more robust. This paper focuses on the detection and mitigation capabilities of a software-based Controlled Reception Pattern Antenna (CRPA) as part of a wider study in which different detection and mitigation methods are tested and compared. The proposed CRPA uses eigenvalue decomposition to determine the weight vector and is combined with MUltiple SIgnal Classification (MUSIC) for detection purposes. Simulations are used to test the software CRPA for its robustness against different types of interference in static and dynamic scenarios. The test method and processing pipeline are described. Initial results show the CRPA algorithm under test is capable of detecting and mitigating different types of interferences, and mitigation can help a receiver to maintain a position velocity time (PVT) solution for higher levels of interference power. Keywords: GNSS; CRPA; MUSIC; jamming; spoofing; detection; mitigation; aviation
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    Satellite Navigation Signal Interference Detection and Machine Learning-Based Classification Techniques towards Product Implementation
    (MDPI, 2023) Rijnsdorp, J. ; Zwol, A. van ; Snijders, M.
    Many critical applications highly depend on Global Navigation Satellite Systems (GNSS) for precise and continuously available positioning and timing information. To warn a GNSS user that the signals are compromised, real-time interference detection is required. Additionally, real-time classification of the interference signal allows the user to select the most effective mitigation methods for the encountered disturbance. A compact proof of concept has been built using commercial off-the-shelf (COTS) components to analyse the jamming detection and classification techniques. It continuously monitors GNSS frequency bands and generates warnings to the user when interference is detected and classified. Various signal spectrum analyses, consisting of kurtosis and power spectral density (PSD) calculations, as well as a machine learning model, are used to detect and classify anomalies in the incoming signals. The system has been tested by making use of a COTS GNSS signal simulator. The simulator is used to generate the upper L-band GNSS signals and different types of interferences. Successful detection and classification is demonstrated, even for interference power levels that do not degrade the performance of a commercial reference receiver.
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    Advanced Receiver Autonomous Integrity Monitoring (ARAIM) for Unmanned Aerial Vehicles
    (MDPI, 2023) Snijders, M. ; Engwerda, H.J.A. ; Fidalgo, J. ; Dominguiz, E. ; Moreno, G. ; Duque, J.P. ; Martinez, J. ; Martini, I. ; Sgammini, M. ; Boyero, J.P.
    Advanced Receiver Autonomous Integrity Monitoring (ARAIM) is an evolution of the currently used aviation-focused Global Navigation Satellite System integrity service, Receiver Autonomous Integrity Monitoring (RAIM). Where RAIM supports only lateral navigation, with its adaptations including multiple frequencies and constellations, and with the use of Integrity Support Messages (ISMs), ARAIM also supports vertical guidance. Although these techniques were designed to serve the aviation community, ARAIM could be used in a wide range of applications, especially safety-critical applications. With further evolutions, ARAIM could also be extended to cover more demanding applications in various sectors. This work reports the outcomes of the study of the applicability of ARAIM for the Unmanned Aerial Vehicle (UAV) sector. Keywords: integrity; ARAIM; GNSS; UAV; HAS; sensor fusion
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    The Group of Responsables “Aerodynamics (GoR AD)” : An Overview of activities and Success Stories
    (ICAS, 2022) Mingione, G. ; Coustols, E. ; Monge, F. ; Ven, H. van der ; Richter, K. ; Tormalm, M. ; Cavalera, L.R. ; Stefes, B. ; Pagan, D. ; Eliasson, P. ; Mallet, M. ; Gemma, R.
    The GoR AD is active in initiating and organizing basic and applied research in aerodynamics and aerothermodynamics. Aerothermodynamics is closely related to space operations and flight through the earth’s atmosphere at very high speeds. Aerodynamics is a cornerstone of aeronautics and one of the primary design disciplines to determine the shape of the aircraft. Environmental issues are of great concern in aeronautics for civil aircraft and advanced aerodynamic design will have a significant impact on fuel consumption and the noise of aircraft. For military aircraft, the requirements of stealthy operation require new aircraft shapes to be considered and these shapes must be aerodynamically effective. The GoR AD remit covers aerodynamics, aeroacoustics, and aeroelasticity. The GoR AD is supporting a multi-disciplinary cooperation with the other GARTEUR Groups in areas where a mono-disciplinary approach is not meaningful. The Group is active in experimental, theoretical, analytical, as well as in numerical fields of aerodynamics to support the development of methods and procedures. Work in experimental areas is performed mainly to obtain valuable data for the validation of methods. Measurement techniques are developed and refined to increase accuracy and efficiency of experimental investigations. Other numerical studies give insight in the mechanisms of basic flow phenomena.