Discontent grows over restrictions on GPS data


  • Lynn Teo Simarski


A current trade magazine ad, headlined “Selective Availability,” features the Mona Lisa with pieces missing from her face. To those in the global positioning trade, including many geophysicists, the ad aims a graphic jab at the Air Force's controversial policy of selective availability (SA), which denies the public the full benefits of its Global Positioning System in the interest of national security.

Civilian users of the Department of Defense's Navstar Global Positioning System are at odds with the military over who should have access to a technology that can be used to navigate ships and planes, monitor the rate of strain along a fault, and even guide a satellite. Since SA was switched on again at the beginning of July, after being cut off during the Persian Gulf war, the debate has heated up anew.