There are many apps available to purchase that advertise reliable location information including emergency services, navigational and social networking apps. A GPS receiver provides accurate location and time to the user. A study of 3G iPhones, which were the first integration of Assisted GPS, WiFi positioning and cellular network positioning available to the general public, evaluates the accuracy of location obtained using all three modes on a 3G iPhone.
it was concluded that the performance of Assisted GPS on the iPhone at outdoor locations was substantially poorer than that achieved using a consumer-grade GPS receiver. The positional error for Assisted GPS was quite a bit larger compared to autonomous GPS. The average RMSE value for ten 20-minute tests was 9.0 m horizontal and 10.6 m vertical, several times larger than those for the consumer-grade GPS receiver. This is because the concessions that are made in the design of the Assisted GPS hardware on the iPhone, including antenna, power and other considerations.
Zandbergen, P.A. Accuracy of iPhone Locations: A Comparison of Assisted GPS, Wifi and Cellular Positioning, Transactions in GIS, 2009, 13(s1): 5-26, (Department of Geography: University of New Mexico).
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Zandbergen, P.A. Accuracy of iPhone Locations: A Comparison of Assisted GPS, Wifi and Cellular Positioning, Transactions in GIS, 2009, 13(s1): 5-26, (Department of Geography: University of New Mexico).
أكثر...