Sunday, February 21, 2016

Accuracy of GPS positioning on the iPhone 3g


This study presents an evaluation of the accuracy of locations obtained using Assisted GPS (A-GPS), WiFi positioning, and cellular network positioning modes on the 3G iPhone. Results indicate that A-GPS locations obtained using the 3G iPhone are much less accurate than those from regular autonomous GPS units (average median error of 8 m for ten 20-minute field tests) but appear sufficient for most Location Based Services (LBS). WiFi locations using the 3G iPhone are much less accurate and fail to meet the published accuracy specifications.
Positional errors in WiFi also reveal erratic spatial patterns resulting from the design of the calibration effort underlying the WiFi positioning system. Cellular positioning with the 3G iPhone measures as the least predictable and least accurate positioning method. It can sometimes be off be several miles. The above pictures shows from a GIS perspective the positioning and accuracy of each type of GPS tracking. It clearly shows that GPS positioning is the most accurate, however, even still it can be hard to pinpoint the exact location. However, as time goes on, these GPS systems, including cellular positioning, will continue to become more advanced and more accurate.

Zandbergen, P. A. (2009). Accuracy of iPhone locations: A comparison of assisted GPS, WiFi and cellular positioning. Transactions in GIS13(s1), 5-25.
I have acted with honesty and integrity in producing this work and am unaware of anyone who has not. - Daniel Buffington

3 comments:

  1. Interesting. The cellular position is significantly less specific than the other GPS methods. Did the study say what exactly influences this wider location range for cellular positioning? I understand GPS is obviously going to be more accurate, but is this accuracy primarily because of less errors in spatial patterns and calibration?

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  2. This is very interesting, I wonder if there have been similar studies about more up to date positioning systems. This could be helpful when buying a new house to look at and see if the location will have better signal in your area.

    ReplyDelete
  3. This is very interesting, I wonder if there have been similar studies about more up to date positioning systems. This could be helpful when buying a new house to look at and see if the location will have better signal in your area.

    ReplyDelete