Precision of positioning systems analysis http

Precision of positioning systems analysis

https://www.globe.gov/documents/2631933/6965868/42534991.pdf


Quote:
Assisted GPS (A-GPS), WiFi positioning and cellular
network positioning. This study presents an evaluation of the accuracy of locations obtained using these three positioning modes on the 3G iPhone. A-GPS locations were validated using surveyed benchmarks and compared to a traditional low-cost
GPS receiver running simultaneously. WiFi and cellular positions for indoor locations were validated using high resolution orthophotography. 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 (median error of 74 m for 58 observations) and fail to meet the published accuracy specifications. Positional errors inWiFi also reveal erratic spatial patterns resulting from the design of the calibration effort underlying the WiFi positioning system.

Cellular positioning using the 3G iPhone is the least accurate positioning method ( median error of 600 m for 64 observations), consistent with previous studies


Median error of close to 2000 feet ! What use can you have for that ???

No wonder NOBODY provide cell only solutions for positionning, heck its 6-2/3 football fields average error in positionning !