Use android compass, accelerometer, and gyroscope to get current position

Question

I'm new to android programing. I know how to get a position of a user in outdoor environment using GPS.

But i'm faced with a problem to find the location of a person inside a building where you don't have GPS available.

I can handle the coding part but i need an idea in how to use compass, accelerometer, and gyroscope data or any other sensor data except GPS to get the current position of the user inside the building after you pass the compass, accelerometer, and gyroscope data to the server. Here consider that the inside of the building is mapped.

Sorry if this is a stupid question.

Answer 1

Indoor locationing is quite difficult, if not impossible today.

What works is mounting Low energy Blue Tooth "Beacons" at multiple places in the building, and use that as info. (see ios Beacons) (But you have to manage that yourself, relation between beaconID and location inside bulding).

With compass, accelerometre and gyroscope you will not have (much) success: In this Google Tech Talk video it is quite detailed explained why a gyro / accelerometer (relaive) navigation cannot work because the slight inaccuracies accumulate within 2 or 3 seconds so strong that you cannot use the result. This is cause by the double integration, see video at 23:30.

Private WLAN (inside your building) triangulation can work, but not inside an (limited) phone which does not give you the info which WLANs are vissible, at which strength.

What remains the already build it GSM-Cell or Wlan location in your smart phone for indoor usage.

There is one further approach:
Evaluating the magnet fields of an building.

This can work, and at least one company works on that, but you have to calibrate that for each building.
But this is more a reasearch topic, than a well known technic.

Further info
My Algorithm to Calculate Position of Smartphone - GPS and Sensors

Answer 2

It sounds like you intend to perform inertial navigation using accelerometer data based on the last good GPS fix. I think you'll find this is not feasible on a mobile phone. Accelerometers used in inertial navigation -- for example, in aircraft -- have to be extremely accurate and highly calibrated to minimize errors. Even then, all inertial systems drift over time. With the relatively low accuracy of a phone, these errors will accumulate quite rapidly and render your position solution unusable very quickly.

Without GPS, most phones can still give you a rough position estimate using cell-site multilateration. This is nowhere near as accurate as a GPS fix, but it's better than nothing.

See also this excellent discussion of indoor locationing (inertial navigation is mentioned there too): Android accelerometer accuracy (Inertial navigation)