How does Google Indoor Navigation work?

Question

For a project at my university I have to collect information about Google Indoor Maps. I spent several hours searching information about how Google Indoor Navigation really works. I've found several links on how to create Google Floor Plans like this:

http://support.google.com/gmm/bin/answer.py?hl=en&answer=1685896

And how you can improve location accuracy with the Google Maps Floor Plan Marker app:

http://support.google.com/gmm/bin/answer.py?hl=en&answer=2667756&topic=1685871&ctx=topic

They say the app collects public broadcast data. But nowhere information about which information is collected and how. Several discussions here and a few articles I found say that google uses wifi-access points and the cellular antennas for indoor positioning. But I couldn't find any official information from Google, which I can use in my project.

Can you suggest me where I can find answers to the following questions:

1. How does the Google Maps Floor Plan Marker really work? Which information is collected and how? A official technical Google paper would be nice, so I can use that for my work.
2. How can I increase the accuracy of the Google indoor navigation, by adding Wifi Access Points, Bluetooth stations or other technology?
3. How can I add additional information like Emergency exits and toilets to a floor plan, so the user can navigate with his smartphone to this special points?
4. Is it possible to add information about rooms, so the user can tap with the finger on them to get additional information? For Example which department is situated in this room and so on?

I found a lot stuff about indoor positioning and indoor navigation. But nothing about how google uses them.

Thanks in advance.

Answer 1

This project just provides maps for indoor places. It doesn't do anything special to augment navigation in these places beyond the standard (GPS, WiFi, etc).

When they talk about (augmenting) positioning with Wifi and Cellular data, they are talking about the same stuff they use on the regular Google maps. This data is collected from cell tower info, and the Wifi stuff is sniffed from the Google street-view cars and then augmented by user-data as people with devices come into contact with these devices and send info back to Google.

It is not very accurate - or even accurate as GPS. It is kind of a "ballpark" estimate. For example, if a Google street-view car detected your WiFi signal when it drove by your house - if you had no GPS, and Google Maps saw your WiFi box, it could estimate that you were somewhere within a few hundred feet of where the Google Street View car detected the signal.

Not as accurate as GPS - but not too bad if you conciser within a few hundred feet better than "no idea". In short - these sources to not give you better or more refined positioning of indoor places. They would be good - for example - to be able to tell you that you are in that particular building if you were inside, and out of GPS coverage.