Thursday, May 26, 2016

Accuracy of iPhone Locations

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 meters horizontal and 10.6 meters 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).

1 comment:

  1. I thought this was particularly interesting and found the data chart about the position of error to be the most intriguing. I figured it was more accurate when Wi-Fi was enabled but I did not know it was that much more accurate in terms of cumulative frequency. I would be curious to see the same data but using the newer developments of the iPhones that came out after the 3.