Jammertest, held annually in Andøya, Northern Norway, is the world’s largest open test for evaluating the resilience of Global Navigation Satellite System (GNSS) technologies against jamming, meaconing, and spoofing threats. Set in a remote Arctic location ideal for high-power interference testing with minimal societal impact, the event brings together a wide range of participants, from academia and industry to government agencies, to conduct real-world GNSS interference testing from a comprehensive and up-to-date Test Catalogue. Organised by a coalition of Norwegian authorities, Jammertest offers a unique environment and an inclusive approach to foster advancements in GNSS resilience without relying on strict regulation. This paper describes the background, approach, and technical setup, such as the transmissions, for the test week.