KSJohn Posted May 4, 2011 Share Posted May 4, 2011 Kind of a dumb question in this day and age, but when was the last time the satelites were scrambled or turned off to cause the GPS units we all use to be inaccurate? I remember when I bought my first GPS in about 1998, it had accuracy to 200 feet or so. Quote Link to comment
+mpilchfamily Posted May 4, 2011 Share Posted May 4, 2011 It was in 2000 when the Sats became available to the public free and clear. Quote Link to comment
+user13371 Posted May 4, 2011 Share Posted May 4, 2011 Selective availability was turned off a little over 10 years ago -- which actually inspired the origin of geocaching. Quote Link to comment
KSJohn Posted May 4, 2011 Author Share Posted May 4, 2011 Did they get shut down on 911? I honestly cant remember and seems like I had other things on my mind at the time.. Quote Link to comment
+Mark+Karen Posted May 4, 2011 Share Posted May 4, 2011 Not sure, but they can't really shut it down now, there are too many critical applications that depend on GPS working. Quote Link to comment
+mpilchfamily Posted May 4, 2011 Share Posted May 4, 2011 DOD still has control over the sats and can shut down availability by region if they have to. They can cause the signals from sats to be encrypted so only they have access. Quote Link to comment
+janandsteve Posted May 4, 2011 Share Posted May 4, 2011 Selective availability was turned off a little over 10 years ago -- which actually inspired the origin of geocaching. On May 2, 2000 "Selective Availability" was discontinued as a result of the 1996 executive order, allowing users to receive a non-degraded signal globally..... And the first cache was placed on May 3, 2000 - 11 years yesterday...... Quote Link to comment
+Egnix Posted May 5, 2011 Share Posted May 5, 2011 DOD still has control over the sats and can shut down availability by region if they have to. They can cause the signals from sats to be encrypted so only they have access. That's not technically correct. The civilian signal (L1) is not and cannot be encrypted. However, the accuracy provided by the signal can be degraded (i.e. "selective availability"). Quote Link to comment
+ecanderson Posted May 5, 2011 Share Posted May 5, 2011 There were some DOD jamming exercises in February/March that played heck with reception for a while (on and off for about a month). Seemed to be more of an issue in the southeastern U.S this time. NOTAMs issued by the FAA warning pilots of unusable areas. They can play whatever games they want, whenever they want. Similar tests were performed on the west coast of the U.S. back in 2006, IIRC. Quote Link to comment
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