GPS Availability in NC

C

creweite

Pre-takeoff checklist
Joined
Jul 29, 2013
Messages
126
Display Name
Creweite
Flew by airline into Greensboro for Thanksgiving, and while here tried to bring up my tablet aviation apps. Thought my device was tango uniform as it did not detect any satellites, then found non on my phone. Then later on both were able to lock on. Is this normal in NC or are the military deliberately screwing things up? Problem was the same over several days,
.
 
Been flying in that area for 20 years and never had a burp on FF or anything else. If you are referring to within the airliner, no idea.


Sent from my iPad using Tapatalk
 
It was probably just poor sattelite reception at your location. Bad view and not enough satellites in the visible sky. I had to give up Direct TV because there is too much forest around my house, blocking a reliable signal. GPS reception here is as good and as bad as anywhere else. Never a problem for me, except on the ground or in certain segments of an airline flight. Here or anywhere.
 
Your GPS had to "find" where its new location is. Not uncommon after moving it a big distance with it turned off.

I had a portable car GPS that took around 24 hours to find its new location after I carried it 2500 miles from its previous location.
 
This was on the ground with no obstructions, and the tablet had already pinpointed the location a couple of miles north on Air Harbor. No lock until after mid day which made me wonder if it was selective availability.
 
GPS is a pretty weak signal, and I guess it's possible something near you was "making noise" on the freqs or sideband(s)?
 
Selective availability only screws up the accuracy of the signal to the tune of hundreds of feet. Sometime in the 2000 time frame, President Clinton issued an executive order that GPS selective availability was not to be used by the military and it has been that way ever since. I agree with Zeldman, your GPS had to refresh its location when it started up because of the large movement of position between powering off and back on.
 
eman1200 said:
the GPS satellites were originally programmed with NC being in the southeast. now that PoA has set them straight they have to be reprogrammed.
Click to expand...

Whoa! Wait one ******ned minute. Are you caving in to a certain person from Alabama and his misguided beliefs on what constitutes the southeast? I am so disappointed in you.
 
What tablet and what GPS? Without that info, I can say that all of the possibilities given are possible and more. But you didn’t say, and it could matter.

Why? If the tablet uses AGPS from the cellular network for “GPS Cold Start” when you’ve moved significantly since last position update, and there’s no cellular coverage on the bands it uses...

There’s a lot of reasons it might not have been working, but SA isn’t one of them.
 
denverpilot said:
What tablet and what GPS? Without that info, I can say that all of the possibilities given are possible and more. But you didn’t say, and it could matter.

Why? If the tablet uses AGPS from the cellular network for “GPS Cold Start” when you’ve moved significantly since last position update, and there’s no cellular coverage on the bands it uses...

There’s a lot of reasons it might not have been working, but SA isn’t one of them.
Click to expand...
 
Yet another reason why VORs should not be decommissioned. If anything this money should be used to build more VORs. VORs are easy to fix. Many cars have radios.
The FAA nonsense about it being "too expensive to repair VORs" seems misguided.
 
Tablet is an Asus. An app that shows the satellites would pick up one of two only at very low levels and then they would disappear. A hard has a useful tool that shows satellites in view and positions. I have that on my phone and it would show nothing at times and then later more than enough for a lock. Well Delta back to FL today.
 
creweite said:
Tablet is an Asus. An app that shows the satellites would pick up one of two only at very low levels and then they would disappear. A hard has a useful tool that shows satellites in view and positions. I have that on my phone and it would show nothing at times and then later more than enough for a lock. Well Delta back to FL today.
Click to expand...

Could have been local interference, just poor timing on the geometry, etc... if you confirmed there were only two satellites being received that isn’t enough for a good math solution for the GPS chipset. Yup.

See any Army kids out playing anywhere nearby? Heh.

Have fun on Delta...
 
You must log in or register to reply here.
Back
Top