The Global Positioning System (GPS) offers numerous benefits to people around the world. Vehicle manufacturers use the system for navigation in their cars, cell phones use GPS to triangulate the user's location, and some applications use the system to track workouts. However, there are numerous military applications for GPS. Planes use it for guidance, warships use it to cross the ocean, soldiers use it on each other on the ground, and guided bombs use it to strike within a few feet of their target. The 1967 Outer Space Treaty expressly prohibited the placement of nuclear or weapons of mass destruction in space. While GPS is none of these, it is a weapons system vital to our national security. This research paper will analyze the history of GPS, military applications of GPS, threats and vulnerabilities of the GPS system, and its future uses as a weapons system. HISTORY OF GPSWhile GPS satellites are launched, operated, and maintained by U.S. Air Force personnel, the idea for a navigation system originated with the U.S. Navy. As Russia won the space race by putting Sputnik into orbit, George Weiffenbach and William Guier, of the Applied Physics Laboratory (APL) at Johns Hopkins University, determined that they could locate Sputnik at any position within its orbit. They were able to do this by monitoring the Doppler shift of Sputnik's signal as it traveled through space. With this in mind, the two determined that if they could see the Doppler shift, so could a sensor here on Earth. This information can then be transformed into navigation data. The two then went to work within the APL developing a system for the US Navy called Transit. Transit, also known as Navy Navigation Satellite Sy...... middle of paper ......nt GPS launch vehicle tracked with GPS rather than radar. The American land surveyor's website. May 20, 2014. Accessed May 28, 2014. http://www.amerisurv.com/content/view/12658/.Air Force website. "Mq-9 Reaper." August 18, 2010. Accessed May 29, 2014. http://www.af.mil/AboutUs/FactSheets/Display/tabid/224/Article/104470/mq-9-reaper.aspx.Wilson, J.R. “Electronic Warfare: The Game of the cat and mouse continues.” Military and aerospace site. September 9, 2013. Accessed May 29, 2014. http://www.militaryaerospace.com/articles/print/volume-24/issue-9/special-report/electronic-warfare-the-cat-and-mouse-game -continues .html.Everstine, Brian “Pilots Turn Off GPS and Other Instruments to Train for Future Wars.” Air Force Times website. October 17, 2013. Accessed May 29, 2014. http://www.airforcetimes.com/article/20131017/NEWS04/310170007/Pilots-shut-off-GPS-other-tools-train-future-wars.