The SENTINEL project was supported by Innovate UK (formerly the Technology Strategy Board (TSB)). Its roots lie in an earlier TSB-supported project, GAARDIAN. SENTINEL set out to examine various aspects of the emerging threat from low-cost commercially-available GPS jammers. Whilst those who have been close to the project now take the threat from such jammers almost for granted, this was not the case when the work began in 2008.  Matters that now seem clear were then emerging unknowns still requiring corroboration, expert knowledge, testing and trials.

This report brings together diverse aspects of SENTINEL. These include: the SENTINEL platform; long-term test results from it; descriptions of jammers and identification of their provenance; descriptions of trials using jammers; videos and press articles arising from SENTINEL exploitation and dissemination activities; and a review of areas in which research would be justifiable in future.

The project found that the problem is clearly getting worse with some locations detecting 5 to 10 events per day; over 50 web sites selling jammers and law enforcement seizing much more powerful jammers with much greater ranges and coverage. Whereas GPS was the only satellite PNT system under threat in 2008, now it is all the GNSS frequencies including Galileo.

One important conclusion that became evident from the work on GAARDIAN and SENTINEL; the GPS jamming threat is getting worse; most people don’t yet ‘get it’; and a ‘Black Swan’ event will happen in the UK, just as it did in South Korea.