The iPhone 3G was the first phone to use the three positioning technologies. The three technologies are assisted GPS (A-GPS), WiFi positioning and cellular network positioning. In this study we see the evolution accuracy of locations obtained using these three positioning modes. Results show that A-GPS in the iPhone are less accurate than the normal autonomous GPS. WiFi locations in the iPhone 3G are much less accurate and fail to meet the specifications required. Positional errors in the WiFi makes the iPhone the least accurate positioning device. Pros and cons of the three positioning technologies are presented in terms of coverage, accuracy and reliability, followed by a discussion of the implications for LBS using the 3G iPhone and similar mobile devices.
Zandbergen, P. A. (2009). Accuracy of iPhone locations: A comparison of assisted GPS, WiFi and cellular positioning. Transactions in GIS, 13(s1), 5-25