iPhone 3G GPS Problems?

[Daiden]

Anyone having problems with their GPS? The first day I got the phone, the GPS worked wonderfully and got a great signal. Three days later, driving down the same highway, the signal was spotty at best and the little dot would often move far off the freeway then back on or jump all over the place. This has happened two days in a row.

Now, this could just be normal GPS behavior, as I've never owned a GPS unit. Anyone have any insight? Is there a problem or are these things just quirky for a few days then they work again?

 

[MegaBit]

Same Here

The first day or two it worked great. As soon as Maps opened it would find me, now it doesn't. It searches and searches and then times out. Or, it thinks I'm in Chandler Arizona, not Seattle!

I had to exchange my 1st unit due to a faulty camera and the new unit found my GPS location quick at first, but now doesn't find me at all (at least today).

I had one thought to add:
The iPhone uses assisted GPS (A-GPS) and that means it gets ephemeris data (satellite location info) from the network to rapidly resolve its search of the sky for signals. So... if the A-GPS data is not readily available (from 3G network or WiFi) it may take a full sky search, called a cold start, and that's about 15 minutes on a low power GPS chip like the one in the iPhone. So my assumption is that the data service for ephemeris data is down or slow or something.

 

[Cubsfan]

This get better for anyone? Usually mine will work if I turn it off then turn it back on. Not sure what the problem is.

 

[StingerT125]

I got mine on the 11th and I haven't noticed any problems with the GPS. It's always located me quickly and seems to track dead on.

I really like the fact that you can use the satellite maps with the tracking instead of just using the street maps.

 

[higgalls]

if the A-GPS data is not readily available (from 3G network or WiFi) it may take a full sky search, called a cold start, and that's about 15 minutes on a low power GPS chip like the one in the iPhone. So my assumption is that the data service for ephemeris data is down or slow or something.

Surely cold start on a low power GPS chip isn't 15 minutes? Most GPS chips coldstart within a minute. Can a low power GPS chip be THAT much worse?

The new SkyTraq extremely low-power GPS chip cold starts in 35 seconds: http://www.eetindia.co.in/ART_8800486309_1800000_NP_935849b1.HTM

 

[rmschmidt]

Mine works fine, no issues?

 

[MacScho]

was on the train today trying to use gps. takes ages to get a blue dot, and when i finally get one it doesnt move as quick as the train is, and when it does it moves into fields and houses and stuff. cant really find much use of the gps whilst its like this. any ideas?