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How well does this work? I've never even had much luck getting my phone to detect "north" as accurately as a $3 compass.
Two issues:

1. I have to question the effectiveness of using 'magnetic anomalies' to determine absolute position. Isn't the sensor just reading one value (magnetic field strength)? Couldn't that be anywhere on the map with that value? Do people have to turn it on at a specific starting point?

2. It says 'communicates with the API' while tracking. Most large buildings that I've been in like a conference center have marginal data reception.

Regarding 1., my phone reads strength and inclination of the field. I suppose that these two, coupled with a compass, could in theory give enough information to collapse the belief state to a single position. Moving a bit should give you enough data to further ensure precision.

Either that, or WiFi. :)

(no expertise here)

How do you get 'inclination' of the field? Is it based on phone orientation? If so then you just opened up a lot more possibilities for position. Also, in this solution the phone doesn't know you're moving. It just sees: magnetic field is changing...

You must have to start it at a specific place, or tell it where you are when you start it (eliminating the 'where am I' use case).

I have some experience with indoor location tech, but not magnetic fields. If I had to guess (and I do) I'd suspect that the algorithm depends on consensus based on traffic/usage. The map's gonna change regularly, but if enough people use the technology you can take the algorithm's guesses for everyone and start to build a confidence weight for your prediction, weed out anomalies, and update your understanding of the magnetic fingerprint of the space over time. I'd also assume it uses GPS to get your bootstrapped whenever possible, ie: sort out what entrance you came through, use pathfinding over time to get some limit the possible locations you might be in currently.
I find it hard to believe that they have legit Trademarks on the phrases "Floor plans" and "Map Creator".

http://www.indooratlas.com/technology.html

I did a US trademark search and did not see anything of theirs for "floor plans".
There wouldn't be, its a (TM) not an (R).

A (TM) is for an unregistered trademark, you own the IP of it though your use of it in the marketplace. This is what they have, and in fact anyone could have. In reality the (TM) is there to indicate you intention to protect it.

An (R) is for the registered trademark, as the name suggests you register it with your local trademark authority. It provides grater protection and is easer to take people to court over the misuse of.

(TM) also means that you've submitted a trade-mark application.
Not necessarily: "In the United States, neither federal nor state registration is required to obtain rights in a trademark. An unregistered mark may still receive common law trademark rights. Those rights, for example, may extend to its area of influence—usually delineated by geography. As such, multiple parties may simultaneously use a mark throughout the country or even state. An unregistered mark may also be protected under the federal "Lanham Act" (15 USC § 1125) prohibition against commercial misrepresentation of source or origins of goods. Unregistered marks are also protectable in the United States under Lanham Act §43(a)."

http://en.wikipedia.org/wiki/Unregistered_trade_mark

What happens when you move large metal objects around? Say a large file cabinet or a safe? The local 'anomalies' are going to change.
Given that mobile phones have wires and electricity then they are creating small magnetic waves which will impact others.

That all said this technolody is very suitable for underwater GPS were a GPS signal does not penetrate the water due to weakness and how bad radio travels thru water in general.

So given that I would have to questions if the military don't already use something very similiar in submarines. Lets say I'd be very supprised if this was not being already utilised in some form or another in that feild.