Ago some weeks i need to test some GPS based software (ofcourse i need to try some navigation softwares)
My fist uncleared question is with this devices is: Why i need ACTIVE SIM card for use the GPS module ?
The response can be is very wide. So finally i resolve the problem with put inside a VALID working SIM card, the GPS receiver works wheel in both cases without major problems.
But i share some thinks about this with us.
1. the GSM connection its very easy to create, the signal is more strength generally (most part of case the phones is used in city’s or with good signal area)
2. The GPS signal is more complicated to handle, sometimes the description of the satellite data is slow and depends on the area coverage, in most of case the GPS signal is not very good in the city’s (buildings, trees etc.)
3. For better working the phone first time get infos from GSM service about the location, secondary makes the synchronizations with the satellites. maybe the second event is some second, both sometimes can be some minutes (in my case 5-7 min).
1. If you have a Phone with AGPS support its very good for Mobile Service Company’s to block this options, until don’t use a valid / working SIM card. It’s good for bussines.
2. So you need to buy some SIM card for use the Phone 😉 (Apple & others)
1. Technically with the GPS signals some Governmental Services can you find everywhere with some punctuality. Generally used satellites have some distortion like the punctuality is between some 10-20 meters, comparative the military GPS satellites have bellow 1 meter this precision.
2. When you are need to use the SIM card and the GSM modules, this Services can find more better. When the GPS signal its not works the GSM works because your phone works ;). So you cannot hide himself from visual area of this services.