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I have an iPad 2 w/ 3G that has a consistently accurate GPS. It always seems to be off by a 1/2 mile or so.THis occurs when the wifi is turned off and the ipad is relying on the SIM card and internal GPS.
Any thoughts of what would cause the problem?
Is this a good question?
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Some areas are harder to triangulate as the satellites are close to the horizon (north & south polar areas).
When you are in a dense city triangulation can be tough as well as the line of sight can be blocked by large buildings.
This is why a hybrid solution using satellites, Cell towers & WiFi AP's is used to improve the accuracy of global positioning.
Also remember the public GPS signals are slightly phased over the military GPS signals which can do ionospheric correction (8 meters/26 feet or more near the poles). Here's the US Governments web site that gets into all of this: GPS Accuracy
With that said, compare your iPad to another iPad (or other like GPS device) to see if the GPS services are damaged. If they both react the same the issue is your location.
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6 Comments
Where are you in the world?
by Dan
Halifax, Nova Scotia. It's definitely the device as my i phone is perfectly accurate. The iPad is always off by a half mile distance in comparison though.
by Brian
Well, you are up there near the pole ;-} Even still if your iPhone is showing an accurate location I would say your iPad needs repair. Sadly, it sounds like the logic board has a problem. Was it damaged at one point (dropped or had gotten wet)? Was it serviced by someone?
by Dan
It's one I've fixed up. I've replaced the digitizer, power /volume flex and wifi antenna and straightened out the frame around the dock connector.
No signs of any other issues with the logic board though. Everything else seems OK. Wonder if a system wipe & restore would help?
by Brian
Can't hurt to do a wipe & restore. I think this is a timing issue within the cellular chip were the GPS signals are processed. Here's a good write up: How Global Positioning Systems Work.
by Dan
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