[gipsies]

Accurate Wi-Fi based indoor location positioning already exists, though with different pros and cons. For example, the following system still works reliably when walking around, but may be a bit less accurate. And it requires no calibration https://www.youtube.com/watch?v=foVqKLE4Mpk

That demo is based on the new 802.11mc standard. Surprisingly, this new standard isn't mentioned in the paper. So no comparison between this and their system...