| Author | Message | ||
     Rans (Rans) Senior Member Username: Rans Post Number: 429 Registered: 08-2002 |
I saw this in another LR forum.... Now that we all depend on GPS, keep in mind that it can go away. Starting Wednesday night, Selective Availability was turned back on for North America with an at least 200 meter error. I know a chap in Texas who was using his that night and watched (with a 7 satellite lock) from a stationary location his error go from 5 meters to 200 meters. I've gotten other similar reports from other people on Thursday. Anyone have anything else on this??? | ||
| Paul D. Morgan (V22guy) Senior Member Username: V22guy Post Number: 1347 Registered: 02-2002 |
Randy, This can be done by Executive Order of the President himself. Once the order is given, the controlling authority of the satellites can deselect the accuracy that we civilians receive. This is very very important to security here in CONUS during a time of high alert or war. If my memory serves me correctly, President Clinton ordered the availabilty to increase making our GPS's more accurate. I think it had something to do with finding Monica's house with his Street Pilot.  | ||
| Michael Noe (Noee) Senior Member Username: Noee Post Number: 511 Registered: 03-2002 |
GPS in Space | ||
| Leslie N. Bright (Leslie) Senior Member Username: Leslie Post Number: 1923 Registered: 02-2002 |
Paul's right: SA was turned off in May 2000, and there are no plans to turn it on. http://www.igeb.gov/sa/faq.shtml Note the second statement, which happens to be what they'll do in this current engagement: they can control the GPS signals in certain areas, so that usage in the US will be unaffected. FWIW, just before the commencement of the ground war in Desert Storm, the accuracy of regular GPS units greatly increased, as SA was temporarily cut off then.... they didn't have enough PPS receivers, and had to use SPS receivers (this back in the "early days" of GPS). If you want GPS info "from the horse's mouth", always check http://tycho.usno.navy.mil/ because you can even find up-to-date status of the constellation there. Or, for info in layman's terms, check http://gpsinformation.net/ as these guys are good at keeping track of any news in the GPS world. -L | ||
| TPH (Snowman) Senior Member Username: Snowman Post Number: 334 Registered: 12-2002 |
Paul- Actually Clinton was using his Street Pilot trying to quickly find a dry cleaner. As we know he failed. S- | ||
| Greg (Gparrish) Senior Member Username: Gparrish Post Number: 1151 Registered: 04-2002 |
Interesting observation this morning I was watching Fox News and they were talking to "Greg Keller" I believe his name is. He was with one of the infantry brigades in a HUMVEE and they were tracking along with an Abrams communication vehicle. Part way through the bit, they turned the satellite video phone his direction and showed him sitting in the front passenger seat and low and behold there was a Garmin 176 attached to the dash with the antenna swiveled up. I was amazed to see a regular looking Garmin on the dash. | ||
| gp (Garrett) Senior Member Username: Garrett Post Number: 1924 Registered: 10-2001 |
she is such a big turd i am sure it was easy to get a lock on her location. even with 50 meter accuracy! | ||
| M. K. Watson (Lrover94) Senior Member Username: Lrover94 Post Number: 713 Registered: 02-2002 |
i have noticed, at least for the last month some odd operations of my Garwin while traveling in the area my work. it is understandable for the need to throw the accuarcy off, but since the gear change and the error to the speed-o-meter i have used my GPS to monitor my speed. i wonder if i could use that as an affirmative defense, " yes officer i am sure you are right and i was going 85, but my GPS said i was doing 35...." mike w | ||
| Todd W. McLain (Ganryu) Member Username: Ganryu Post Number: 175 Registered: 10-2002 |
Greg, Could be the drivers personal GPS. Unfortunatly, the Marine Corp never had enough GPS units to give one to everybody, so alot of us took to carrying our own. Plus, it makes a really nice backup. Todd | ||
| R. B. Bailey (Rover50987) Senior Member Username: Rover50987 Post Number: 446 Registered: 07-2002 |
Military recievers are are able to "unlock" the code with some sort of transponder. So are those units which are used for IFR navigation in aircraft. Makes sense; Iraqi soldiers with a $150 unit could have the same degree of navigation accuracy with the SA turned on. | ||
| Peter (Pete) New Member Username: Pete Post Number: 6 Registered: 03-2003 |
Actually, the gov units use a different signal than us civilians. However, most of the time the gov units use the "civilian" signal to latch onto and then switch to the encoded signal for more accuracy. Of course, if you are able to keep them from getting bombed to nothing, you could set up DGPS transponders in your country to mitigate a lot of the SA signal if it is on locally there in Iraq. Basically, even if you are off by 200 meters, if you had a known point on land that was blasting a signal you'd be able to bring that accurancy down quite a bit. Of course, the hard part is trying to keep something that is sending a pretty clear signal about where it is from getting locked on to by the enemy. pwc | ||
| Leslie N. Bright (Leslie) Senior Member Username: Leslie Post Number: 1925 Registered: 02-2002 |
Yep, civilian signal is SPS, wheras the military has the additional PPS signals as Peter described. We're using thos JADM "smart" bombs that are old-fashioned ordnance that have had the tail section replaced with a computer, GPS, and steerable tail-fins. Enter the coordinates that you want that bomb to go to, drop it, and it sails right to it. $20,000 a pop versus $1,000,000 for a cruise missile.... you get a lot more bang for the buck w/ 'em.... Nah, we're using the GPS signals too much to screw with 'em... yeah, you might see some quirkiness occasionally, but, only momentarily, and nothing big... FWIW.... -L | ||
| Jess Alvarez (Jester) Member Username: Jester Post Number: 134 Registered: 11-2002 |
I used my Garmin Rino yesterday, and had accuracies as low as 16 feet. I dont think its back on. But I could be wrong |
