Ships can be led astray with fake GPS signals. If signals for navigation of vessels are jammed or spoofed, positional and other critical data, such as course and speed, can be affected. Researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) have tested new receiver systems and methods for suppressing interference in a three-day measurement campaign. These systems will allow the detection of future jamming and spoofing attempts. Their effect on on-board sensors can thus be drastically reduced, which in turn contributes to shipping safety.