C4I.org - 10 GPS Vulnerabilities by Lieutenant Colonel Thomas K. Adams, US Army, Ret. Dual Use and Vulnerabilities I take GPS for granted now for land travel and marine navigation. (Well, my Garmin nÃ¼vi needs to go back to the factory, but that's another story.) Obviously the military uses GPS, but what are the vulnerabilities especially if the the system is attacked by a hostile entity? I don't even know how many GPS systems there are and who controls them.