iPhone GPS Without Cell Phone Service
I don't have an iPhone, so I'm not familiar with all its features. So please bear with me. Basically, I'd like an iPod touch with GPS capability. I'm thinking of getting an iPhone but not subscribing to cellular service, since I get an very weak AT&T signal at my home location. Is this possible?
I understand that the iPhone has a built-in GPS receiver chip set and can receive and process the C/A (coarse acquisition) prn code from the constellation of GPS satellites. I'm under the impression that the iPhone doesn't have the capability to process the low bit rate almanac and ephemeris data that is modulo-2 added to the C/A code to make up the SPS (Standard Positioning Service) signal.
My understanding is that the iPhone depends on assisted GPS to obtain the required low rate data, but I'm unclear whether it gets it from cell tower signals or WiFi (Skyhook). If it's WiFi, then I can process the GPS signals and plot location on WiFi downloaded Google maps. I think this would work. Am I mistaken? If the low rate data is obtained via cell tower signal, I guess I'm out of luck. Can anyone clarify this for me?
Thanks
Ray
I understand that the iPhone has a built-in GPS receiver chip set and can receive and process the C/A (coarse acquisition) prn code from the constellation of GPS satellites. I'm under the impression that the iPhone doesn't have the capability to process the low bit rate almanac and ephemeris data that is modulo-2 added to the C/A code to make up the SPS (Standard Positioning Service) signal.
My understanding is that the iPhone depends on assisted GPS to obtain the required low rate data, but I'm unclear whether it gets it from cell tower signals or WiFi (Skyhook). If it's WiFi, then I can process the GPS signals and plot location on WiFi downloaded Google maps. I think this would work. Am I mistaken? If the low rate data is obtained via cell tower signal, I guess I'm out of luck. Can anyone clarify this for me?
Thanks
Ray
G4 Powerbook, Mac OS X (10.5.8)
