# Reduced GPS accuracy in the Southeast



## jis (Jan 29, 2011)

> *FAA warns of ongoing GPS issues in southeastern US due to Defense Department 'tests'*
> 
> anyone planning on using GPS in the southeastern US for the next month or so will likely want to make sure they have a fallback option. That's according to a flight advisory just issued by the FAA, which warns pilots that their GPS signal "may be unreliable or unavailable" due to "GPS tests" that the Department of Defense will be conducting between January 20th and February 22nd.


You can read the whole article here.


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## Trogdor (Jan 29, 2011)

No matter. People will still stare at their GPS when they should be staring out the window at the road in front of them. When it says turn right, they'll turn right. Never mind that they'll turn directly into a tree (or onto railroad tracks, as actually happened at least once). It'll be the computer's fault.


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## jis (Jan 29, 2011)

Trogdor said:


> No matter. People will still stare at their GPS when they should be staring out the window at the road in front of them. When it says turn right, they'll turn right. Never mind that they'll turn directly into a tree (or onto railroad tracks, as actually happened at least once). It'll be the computer's fault.


That's true of hapless people in their cars and trucks feeling technologically savvy because they have a GPS. This notification mentioned is however from a NOTAM targeted at airmen. It is not clear that there has been any general notification at all. Airmen one would hope, actually are a little more knowledgeable about these things and know what the fallback procedures are. 

There is actually a very interesting and informative thread about this on airliners.net where I learned a lot of various navigation aids from past, present and what is coming in the near future. Fascinating stuff.

I guess when people go on and on about how their precious GPS measured a train going 5mph over speed, they need to keep in mind that what GPS sets, specially the cheap ones we carry around say, are not exactly the gospel truth.


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## Devil's Advocate (Jan 30, 2011)

What's with all the GPS hatred? I use GPS-assisted devices all the time, especially when I'm in new areas, and they've been extremely helpful in my experience. I guess that's just not as interesting as blindly bashing everyone who uses them with a brush the size of Kansas. Never mind that there have been people driving where they shouldn't have long before the first GPS satellite was ever launched. In my experience driving prowess has far more to do with the _culture_ of the folks doing driving rather than the specific technologies they employ while doing so. Compared to someplace like India I'd say Americans drive surprisingly well, even those who are cursed with a mind-numbing GPS stuck to their dash.


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## jis (Jan 30, 2011)

daxomni said:


> What's with all the GPS hatred? I use GPS-assisted devices all the time, especially when I'm in new areas, and they've been extremely helpful in my experience. I guess that's just not as interesting as blindly bashing everyone who uses them with a brush the size of Kansas. Never mind that there have been people driving where they shouldn't have long before the first GPS satellite was ever launched. In my experience driving prowess has far more to do with the _culture_ of the folks doing driving rather than the specific technologies they employ while doing so. Compared to someplace like India I'd say Americans drive surprisingly well, even those who are cursed with a mind-numbing GPS stuck to their dash.


Who said anything about hating GPS's? At least I have been using one since the very first hand held one became commercially available.

All that was said essentially is when a device like GPS is used without taking extra care to maintain situational and locational awareness, independent of what the device shows, bad things can happen. The comment was mostly about people who loose situational awareness and still go on either unaware or unwanting to check or both, and those that blindly trust numbers that show up in the way of e.g. speed on a GPS device. It was most certainly not about everyone that uses GPS, or even the entire GPS technology itself.

As for the technology and dependence on it for critical missions potentially without any fallback or capability to crosscheck with independent source of input, that is an entirely different discussion, and a lively one that has been going on airliners.net, as I mentioned earlier in this thread. Naturally, since with RNAV and the NEXTGEN nav systems coming on line this is more of a life and death issue for folks out there in airliners.net, rather than a _gee cool toy_ to play with, as is the case with us railfans. See this airliners.net thread, if you are curious. Very informative and fascinating discussion.

I don't believe that the native driving ability of anyone has any relevance to this discussion. This is mostly about navigating ability and forgetting to keep in mind the accuracy or lack thereof that is inherent in the technology and device being used.


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## saxman (Mar 12, 2011)

To bring an older thread back:

Up until about 2 years ago, about half our fleet at my airline had GPS installed. It didn't really change anything really. We navigated the same using the FMS which calculates based off ground based VOR's and DME. Over the past weeks I've flown into Atlanta but never noticed any anomolies. It really sucks when the FMS goes out though. I've had that happen about 3 times now, and while not a big deal it sure makes us have to do a lot more work.  Navigating the old fashioned way can be a challenge though.


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