habe die Quelle für die erlaubte Verwendung von nicht zertifizierten GPS-Quellen gefunden:

Standard Change CS-SC002b INSTALLATION OF MODE S ELEMENTARY SURVEILLANCE EQUIPMENT

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4. Limitations
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However, the voluntary transmission of additional ADS-B data (e.g. GPS position and velocity) can be accepted when the position and velocity quality indicators report the lowest quality, the equipment manufacturer has stated compatibility with the directly connected GNSS source, and the transponder is not authorised in accordance with ETSO-C166b or equivalent.