I am no tech guru, but I do remember when I had my HTC Touch Pro (windows phone), there was an app that you could download the latest gps info to get a better lock. Maybe this is the reason they say you have to have wifi on to get a lock. Once its updated and downloads the satellite info for your location it will work fine without WiFi.
Imagine if it was turned on in Tiawan during assembly it would have gotten the satellites for that side of the earth, you will obviously be looking for different satellites over here, but it doesn't know that.
Again this is all speculation, but it made sense in my head.
You are absolutely correct. If you move it more than about 300 miles, it can cause it to go flakey. Here are a couple quotes from a website I was just reading about this very problem (here
- I realize this is for a stand-alone gps, but the theory of how they work is the same):
"In order for GPS receivers to function, they need to know three critical pieces of information. These are the current date and time, the receiver's location on the earth
and the location of the satellites in orbit. When a GPS receiver has these three pieces of information, it performs a normal startup procedure, called a "warm start," and will typically begin displaying a position in less than one minute. When a GPS receiver does not have this information, however, it must perform a much slower "cold start" routine that can take up to 20 minutes
. The wide variance between the warm and cold starts highlights the significant challenge that a GPS receiver faces when it must search the entire available sky for a GPS signal that is not much stronger than the overall background noise."
Another important piece of info:
"GPS receivers use two different search methodologies, depending on whether they are performing a warm or cold start. Warm starts are much quicker than cold starts because the GPS receiver knows exactly where to look in the sky to acquire a satellite signal. Sometimes, however, GPS receivers get confused and think they have enough information about the current date and time, their location on the earth, and the location of the satellites in orbit to perform a warm start. When some of the data is wrong, the GPS receiver may never acquire any satellites because it is using a narrow search routine in the wrong area of the sky.
If your GPS receiver does not acquire any satellites within 5 to 10 minutes, force it into its cold start routine, which will cause it to search the entire sky. Check the documentation specific to your GPS model to see how to reset it, or clear its memory."
Lastly, from here
, "[FONT=verdana,arial,helvetica,sans-serif]The receiver may also have to be initialized if it was moved several hundred miles since its last use."
[/FONT] I think it's safe to assume these have moved several hundred miles since their last use, if they were every initialized previously at all.
Turning wifi off like many folks over at XDA are saying to do is likely only exacerbating the situation. A-GPS uses wifi or other data to get a better guesstimate of your location to speed up your initial lock. Also, sitting on your couch trying to do a cold start is just plain silly - get a clear view of the sky. Good, strong signals from a clear sky will help get an initial lock. I had to stop reading the thread over at XDA because it was so littered with inaccuracies and people jumping to conclusions I just couldn't take it any longer.