Wi-Fi geolocation is very accurate (in urban areas) because there are many Wi-Fi access points which which to triangulate and their range is pretty short. I'm surprised the article didn't mention Wi-Fi at all.
> For Android phones, the information we use in addition to satellite signal strengths is usually just the standard GNSS position fix, but can also be Android Fused locations, which may include WiFi-based positioning. Since this location can be very inaccurate, single time instant (one-shot) fusion of GNSS fix with shadow matching likelihoods typically leads to poor performance.
I was thinking the same thing you were. I wonder why they found that it worked poorly for them.
This statement is so absurd that at first I was not even going to respond to it.
That didn't stop one company from doing so... cough cough Google. (https://www.wired.com/2014/04/threatlevel_0401_streetview/)
Also, I have no idea why Uber left out the fact that they are indeed using both the driver and the users WiFi location data.
Notice that they highlighted that they only use Android users....
Would be interesting to see if the accuracy of Uber services deteriorate if the privacy settings on Android were to tightened up....
Here is a useful link for WiFi access point/ cell tower location database [Big, Beautiful Data: Mapbox Visualizes Skyhook Wi-Fi Access Point Location](https://www.skyhookwireless.com/blog/company/mapbox-visualiz...)
I helped launch this project back when Mozilla needed an inexpensive location solution for Firefox OS devices. It is still used for testing the Firefox Nightly channel, though the Firefox Release channel uses Google's location service.
https://location.services.mozilla.com/
Here is a zoomable world map of all the network locations:
Each of the three location methods, UTDOA, GPS, and WiFI are good at different things. They can all get 50m accuracy or better--when they work.
GPS is great outdoors and rural, but has problems with indoors and urban canyons because of sky view, attenuation and multipath. It also needs ephemeris data periodically (ie AGPS) and 5 sat fixes, which can mean 30s to first locate. Obviously WiFi is good if you can get it; it's like a street sign. UTDOA has 5s fix times and works wherever you have a cell signal, indoors or out, and also has the feature it doesn't depend on handset software; it's network based. So you really want all three, plus maybe other weaker methods like CGI, ECID, or CGITA for hybrid locations. They're all good in different cases.
So carriers ARE using two of the three methods as you point out.
But UTDOA is network based (towers), not handset, so it's expensive and carriers hated it. So much in fact, that they colluded to keep it out of the LTE standard [0] and avoid that expense and IP issues.
Skyhook, already dealing with Google [1] was bought by TruePosition, which then vanished into Skyhook since UTDOA was out of the picture. I'm pretty sure there's no UTDOA left in deployment.
So you have 2 out of three handset methods but you're lacking the third. Which means despite new FCC indoor 50m location rules[2], if you're dying indoors with no WiFi, you better not call 911 and expect a good location [3].
This was my point about business. We have the tech on the shelf to make 50m indoor reliably, we just won't.
0. https://finance.yahoo.com/news/trueposition-ericsson-settle-...
1. https://searchengineland.com/skyhook-wireless-sues-google-yo...
2. https://www.fcc.gov/document/proposes-new-indoor-requirement...
3. https://www.iafc.org/on-scene/on-scene-article/concerns-rema...