mudhuggers Posted November 26, 2002 Posted November 26, 2002 I thought this was more common knowledge. . . Regarding my posting earlier today as to whether or not the US Military has encrypted GPS signals yet. . . It seems that the replies I got back were from people who don't know who owns and controls those little things floating around in space. The US military's satelite GPS system can send encrypted or non encrypted signals. The soldiers hand held GPS has the software to decrypt. . . our Civilian GPS's do not. When the military tells the satelites to go "encrypted," our Civilian GPS's are not going to be as accurate, but the Military's will be. Most of us will not be able to tell and for all practical purposes won't care. But if you are GEO Caching and the US is fighting a war, and your readings are off 100 feet or so from the geocaching coordinates, now you know why. There has to be someone out there in goecaching land who already knows this! Quote
+Sissy-n-CR Posted November 26, 2002 Posted November 26, 2002 The people over at sci.geo.satellite-nav can set you straight. I'd wager you can't find a more knowledgable group on this subject anywhere on the internet. CR Quote
Kerry. Posted November 26, 2002 Posted November 26, 2002 Don't worry, know exactly who owns them, what they do and what they can't do and the response is still the same. "Encryption" to some extent in GPS terms has more to do with AS (Anti-Spoofing) than SA but there is a connection. Actually if someone using a GPS can't tell if SA is on or off then they really want to give it away. 100' ain't really a problem as that is even less than the actual spec of 36 metres @ 95 % (worst case scenario). Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote
+The Leprechauns Posted November 26, 2002 Posted November 26, 2002 I think most experienced GPS users know the military purpose of the system. Geocaching started to commemorate the disabling of "Selective Availability" of the signal for non-military users. What we DON'T know is whether the switch has been flipped so that SA is once again enabled. Well, maybe some of us know that, but if they told us, they'd have to kill us. I'm not sure that the government would publish an announcement to inform recreational users that, on November XX, Selective Availability will be turned on (globally or locally) in anticipation of impending military action. So, the comments you received did not relate to SA because the average forum user wouldn't have any more information than you do! x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x Why didn't Noah swat those two mosquitos? Quote
Kerry. Posted November 26, 2002 Posted November 26, 2002 One thing I will add if SA ever goes live again (which it won't) it would take a matter of seconds to be detected, and the fact broadcast that's for sure. That is if the WWW was still alive and running. However if SA was ever required again (over and above Selective Deniability) then one would guess that with things that bad there simply wouldn't be a civil signal what so ever. Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote
+parkrrrr Posted November 26, 2002 Posted November 26, 2002 quote:Originally posted by Kerry:One thing I will add if SA ever goes live again (which it won't) it would take a matter of seconds to be detected Exactly. SA is more than just a positional error. If you're standing still and your GPSr thinks you're going at 2-3 mph in a random direction, that's SA. If all you're getting is bigger errors than you expected, it ain't SA. Quote
+Jamie Z Posted November 26, 2002 Posted November 26, 2002 quote:Originally posted by happytobecaching:It seems that the replies I got back were from people who don't know who owns and controls those little things floating around in space. Well Jimbob, all I know is that I press this here little button, and that arrow there, on this screen see, it points yonder. We just gotta mosey on over thattaway and roust out that stash full 'er goods. We're not all idiots. Probably the biggest reason the replies you got weren't quite what you needed is that this topic has been brought up before. We've discussed several times already about the government turning off the signals or not. A forum search turned up these threads: Did the government turn the GPS Satellites off? Government misinformation More powerful GPS signal Anyone notice a degradation of the GPS signal lately? military takes control of GPS? Selective Availability Selective Availability Selective availability Not all of these relate directly to the question you asked, and some of the threads are old, and possibly outdated... but I think it's clear that this isn't a group of bumbling fools wandering around out in the woods on the whim of their magic boxes. Keep in mind when posting to a public forum, especially one devoted to geocaching, that there are people from all walks of life reading. We have doctors and lawyers in here. We have electrical engineers, people who have played with radio signals all their lives. We have people here who are military. There are a few who work in the GPS industry. (Remember Garmin Pilot? Methinks troll.) I suggest you read through some of the threads on these forums. Sure, many of them are light-hearted, and little-related to geocaching. That just means we're a friendly group, not that we all grew up in Mississippi. Welcome. Jamie Quote
Lyra Posted November 26, 2002 Posted November 26, 2002 I thought Groundspeak owned them Always wear proper caching safety equipment! Quote
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