From Eyebeam's "PRISM Breakup" talks, Oct. 6, 2013. "Tracking, Spoofing and Jamming
 - A Beginner’s Guide to GPS Systems and How They Work (or Don’t)" from Genevieve Hoffman. "As our dependence on smartphones and gps mapping technologies increases, we must come to terms with the fact that our locations are being tracked. Laura Poitras commented in her recent NYT Magazine profile, “Geolocation is the thing,” she said. “I want to keep as much off the grid as I can… I am not going to ping into any G.P.S. My location matters to me. It matters to me in a new way that I didn’t feel before.” What conveniences must we give up in exchange for keeping our physical locations private? This talk will dive deeper into understanding how the Global Positioning System (GPS) works. While GPS coverage is practically ubiquitous, there are aspects where it is vulnerable. Devices, while illegal, can be used to jam GPS frequencies. More sophisticated manouevers can be used to spoof GPS signals. This technique was used to land the US Military drone in Iran in 2011, and research suggests that GPS spoofing could be used to interfere with high speed algorithmic trading."