global positioning system
Geolocation
jamming
http://phrack.org/phrack/60/p60-0x0d.txt
http://sidt.gpsworld.com/gpssidt/Innovation/Innovation-Interference-Heads-Up/ArticleStandard/Article/detail/523633
http://tech.slashdot.org/tech/08/06/27/0426216.shtml