jerm 0 #1 March 19, 2003 In this age of widely available GPS receivers, there are suspicions in high places that, in order to throw off Iraqi units using GPS, the Military may be degrading civillian GPS accuracy, from ~3 meters to over ~100 meters most of the time, and occasionally ~300 meters. Read Here Probably not enough to hose a whole load on a plane with formally decent GPS spotting, but i can't think of many of those that i've been on. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #2 March 19, 2003 Our dz doesn't have one anyway . ____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
diverdriver 5 #3 March 19, 2003 I believe they might be able to degrade the signal in just certain areas rather than the whole system. If they degraded the whole system that would turn off a whole bunch of instrument approaches in the US. Not sure if they want to try and do that globally.Chris Schindler www.diverdriver.com ATP/D-19012 FB #4125 Quote Share this post Link to post Share on other sites
CrazyIvan 0 #4 March 19, 2003 Would you 'spot' from a B-52? __________________________________________ Blue Skies and May the Force be with you. Quote Share this post Link to post Share on other sites
betzilla 56 #5 March 19, 2003 you mean therea re still people out there that "spot?" That's crazy! I thought when the door opened you were just supposed to go... Quote Share this post Link to post Share on other sites
jerm 0 #6 March 19, 2003 Quote Our dz doesn't have one anyway . so your DZ's spotting skills are probably well honed. Unfortunately that's not the case at most turbine DZ that i've been to. Hell, a lot of places seem to have WORSE spotting with GPS. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
jerm 0 #7 March 19, 2003 Quote you mean therea re still people out there that "spot?" That's crazy! I thought when the door opened you were just supposed to go... (Actually seen in the back of an otter) "SPOTTING INSTRUCTIONS: red light: open door green light: Exit" sad.... very sad. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
jerm 0 #8 March 19, 2003 that's what the did before GPS This only applied to civilian GPS, though.. military GPS (which is normally far more accurate than civilian anyway) will be unaffected. Landing without injury is not necessarily evidence that you didn't fuck up... it just means you got away with it this time Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #9 March 19, 2003 Even at the turbine DZ's I go to, nobody looks at the lights anyway, unless there's lots of cloud (in which case we don't jump ) ____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
betzilla 56 #10 March 19, 2003 even if it's not written anywhere, that's what people do. A wise skydiver once told me that if people are yelling at you to go, but the spot sucks, you should offer them a chance to jump before you. That usually shuts 'em up.... Quote Share this post Link to post Share on other sites
skydivegirl 0 #11 March 19, 2003 I don't think you can degrade accuracy in only certain areas. How would that work? There are twenty-something satellites... they would have to distort the clocks in specific ones according to their relative positions (which keep changing). It seems like that would be too difficult to do without compromising accuracy in other locations. And anyway, there are so many benefits (mainly financial) to the civilian use of GPS that I really doubt they'd go back to Selective Availability.Pink Mafia Sis #26 Quote Share this post Link to post Share on other sites
diverdriver 5 #12 March 19, 2003 Actually, they've been running tests in the past months on degrading GPS signals here in the US. They are listed by NOTAM and described in area around certain VORs out west. The area increases with altitude. Out to 400nm in some cases. So, it does seem they can degrade GPS in certain areas if they want.Chris Schindler www.diverdriver.com ATP/D-19012 FB #4125 Quote Share this post Link to post Share on other sites
skydivegirl 0 #13 March 19, 2003 Hmmmmm..... interesting!Pink Mafia Sis #26 Quote Share this post Link to post Share on other sites
AndyMan 7 #14 March 19, 2003 According to the discussion on slashdot, selective availailability will probably be turned on globaly, not regionaly. http://slashdot.org/article.pl?sid=03/03/19/0340247&mode=thread&tid=126&tid=103 _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites
pilotdave 0 #15 March 20, 2003 Ugh. They shut SA off in the first place because they created the ability to turn it back on regionally. Why doesn't the government just lock us all in our homes and not let us go out so we're perfectly safe all the time (except in the bathroom, where 90% of household accidents occur)? Dave Quote Share this post Link to post Share on other sites
indyz 1 #16 March 20, 2003 Screw spotting, I can do that. This is gonna ruin geocaching. Quote Share this post Link to post Share on other sites
NoShitThereIWas 0 #17 March 20, 2003 Quote even if it's not written anywhere, that's what people do. A wise skydiver once told me that if people are yelling at you to go, but the spot sucks, you should offer them a chance to jump before you. That usually shuts 'em up.... That is an excellent idea. I am going to try that next time. Thanks!Roy Bacon: "Elvises, light your fires." Sting: "Be yourself no matter what they say." Quote Share this post Link to post Share on other sites
Ducky 0 #18 March 20, 2003 Quote you mean therea re still people out there that "spot?" That's crazy! I thought when the door opened you were just supposed to go... hee hee funny one! Reminds me of a lil story about my first solo that I posted here last Feb.>> "My AFF didn't cover anything regarding spotting.... So on my first solo when i ended up being first out someone yellled door, i looked out (apparently at nothing) and said seeya, exit! I couldn't figure out why I was so far out when i opened at 4,000. I flew straight into the wind the whole way back never turned even on approach. I made it into the landing area by about 15ft. Later someone approched me and explained the whole green light red light concept to me. I had never noticed the damn lights cuz students were always the last off and all i knew about was separation. Within minutes I approached a few AFF-Is and told them the story they both were sympathetic and admitted that they forget those minor details sometimes. It was a good learning experience though, and without a walk! I spotted the next 5 loads and was even asked by my coach to tell the pilot in which ways to adjust jump run on a few. " kwakSometimes your the bug, sometimes your the windshield. Sometimes your the hammer sometimes your the nail. Question is Hun, Do you wanna get hammered or do you wanna get nailed????? Quote Share this post Link to post Share on other sites
Clownburner 0 #19 March 20, 2003 According to the FAA web site, (http://gps.faa.gov/gpsbasics/SA.htm) "After the attacks of September 11th, the industry buzzed over the possibility of a return to SA. However, on Sept. 17, 2001, the Interagency GPS Executive Board (IGEB), which governs the GPS system, announced the United States has no intent to ever use Selective Availability again." According to the US Navy's GPS Status page (ftp://tycho.usno.navy.mil/pub/gps/gpstd.txt): "1. Selective Availablility (SA) levels set to zero. On May 2, 2000 at 0400 UT, SA levels were set to zero. For more details, check the Interagency GPS Executive Board (IGEB) web site at http://www.igeb.gov. " Of course, your propaganda will vary, but it seems like they'd have to be really careful about using it in the US because of the problems it'd cause with instrument landings on Commercial and GA aircraft... I don't doubt they're nerfing the civilian channels in the middle east, though...7CP#1 | BTR#2 | Payaso en fuego Rodriguez "I want hot chicks in my boobies!"- McBeth Quote Share this post Link to post Share on other sites
diverdriver 5 #20 March 21, 2003 Just checked my GPS and the EPE (Estimated Position Error) is 45 feet. I checked against a known waypoint I set and while standing on the spot it said I was 45 feet away. The EPE had been down to 20 feet so I guess they have some degredation going on but I doubt it would effect my dropping jumpers much. Chris Schindler www.diverdriver.com ATP/D-19012 FB #4125 Quote Share this post Link to post Share on other sites
skydivegirl 0 #21 March 21, 2003 Do you think? Maybe it's the particular receiver you're using. I don't know much about the receivers airlines or other pilots use but is it possible that it's always had that error? Different grades of receivers can vary a lot.Pink Mafia Sis #26 Quote Share this post Link to post Share on other sites
diverdriver 5 #22 March 21, 2003 QuoteDo you think? Maybe it's the particular receiver you're using. I don't know much about the receivers airlines or other pilots use but is it possible that it's always had that error? Different grades of receivers can vary a lot. I use a handheld Garmin GPS III Pilot. When I first got it before SA was turned off I had an EPE of 60 feet. Not bad. Then SA was turned off and the EPE went down to like 20 feet. Now it was up to 45 feet. I'll tell you, if I was always able to fly within 45 feet of course I'd be a shuttle pilot. Quote Share this post Link to post Share on other sites
kallend 1,672 #23 March 21, 2003 Quote Different grades of receivers can vary a lot. Do you have evidence or a reference for that? The signals are digital and the precision timing is done by cesium clocks in the satellites, so it's hard to see how there could be any difference as long as the signal is received at all.... The only sure way to survive a canopy collision is not to have one. Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #24 March 21, 2003 But the electronics in the reciever can vary a lot. Same as pc's - sure they can all run windows, but the speed and reliability can vary from machine to machine.____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
dreamsville 0 #25 March 21, 2003 The next time you're flying, we'll watch very carefully for those 25 feet on the spotting! Yeah, we'll nail the difference| I don't drink during the day, so I don't know what it is about this airline. I keep falling out the door of the plane. Harry, FB #4143 Quote Share this post Link to post Share on other sites
