Mt Whitney Webcam
Mt Williamson Webcam
Who's Online Now
0 members (), 155 guests, and 16 robots.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Unreliable GPS On Left & Right Coasts
#10190 01/21/11 12:35 PM
Joined: Oct 2009
Posts: 2,251
Likes: 1
wagga Offline OP
OP Offline
Joined: Oct 2009
Posts: 2,251
Likes: 1
East coast NOTAM.



"The Notice to Airmen said the GPS tests will be carried out beginning Thursday and are expected to last through February 22. They will cause spotty GPS signals in a several hundred mile radius centered off the coast of Florida."

"During the effective period, test events will be active for 45 minutes followed by 15 minutes of off time."

West Coast NOTAM.


Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII
Re: Unreliable GPS On Left & Right Coasts
wagga #10191 01/21/11 01:09 PM
Joined: Nov 2009
Posts: 595
Offline
Joined: Nov 2009
Posts: 595
Thanks for posting that. I'll be using my GPS tomorrow on the west coast.

FWIW - I used it Wednesday on a hike up Argus, and didn't notice any issues with the GPS track created by the Garmin 60CSx. The only weirdness I've ever noted, and it was very limited, were some stray points created on a hike up Cottonwood Creek Trail (south of Lone Pine) a couple of years ago, and that I believe was caused by echos/bounces where the canyon walls are particularly narrow.

Re: Unreliable GPS On Left & Right Coasts
KevinR #10192 01/21/11 01:48 PM
Joined: Sep 2009
Posts: 8,505
Likes: 103
S
Offline
S
Joined: Sep 2009
Posts: 8,505
Likes: 103
Interesting. Here's another article: Bone in Its Teeth

Here's the GMap4 map of the location of the test center in California: (full screen version)



Re: Unreliable GPS On Left & Right Coasts
KevinR #10194 01/21/11 01:59 PM
Joined: Oct 2009
Posts: 2,251
Likes: 1
wagga Offline OP
OP Offline
Joined: Oct 2009
Posts: 2,251
Likes: 1
I think the disruption is at or above the elevation shown in the various zones. Which means hiking in Florida shouldn't be affected. I've never been there, but I don't think there are any 10,000 foot mountains.

On the other hand, on the West Coast diagram, you can see that one could easily be hiking above the service ceiling of quite a few small general aviation aircraft.

Why is this this happening?. I suspect it has something to do with denying exact geographical information to our enemies, while retaining the facility for our own military. Note that the US launched a heavy (20 tons, size of a city bus) secret military payload from Vandenberg on Thursday.


Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII
Re: Unreliable GPS On Left & Right Coasts
wagga #10197 01/21/11 02:10 PM
Joined: Oct 2009
Posts: 2,251
Likes: 1
wagga Offline OP
OP Offline
Joined: Oct 2009
Posts: 2,251
Likes: 1
Another thought: Some cell phone systems rely on receiving the atomic clock time signal from GPS satellites. Also, the Internet has some reliance on the GPS clocks to synchronize IP package queue/dequeue processes. That would break streaming video and VOIP, but not email & such. Both, however, can use local (internal) clocks to continue for some time.


Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

Link Copied to Clipboard
Powered by UBB.threads™ PHP Forum Software 7.7.4
(Release build 20200307)
Responsive Width:

PHP: 7.4.33 Page Time: 0.064s Queries: 24 (0.059s) Memory: 0.5920 MB (Peak: 0.6542 MB) Data Comp: Off Server Time: 2024-03-28 17:52:35 UTC
Valid HTML 5 and Valid CSS