Indoor Positioning System based on Gyroscope and Accelerometer
Gyros and accelerometers are not enough.
You get position by integrating the linear acceleration twice but the error is horrible. It is useless in practice.
Here is an explanation by (Google Tech Talk) at 23:20. I highly recommend this video.
As for indoor positioning, I have found these useful:
- RSSI-Based Indoor Localization and Tracking Using Sigma-Point Kalman Smoothers
- Pedestrian Tracking with Shoe-Mounted Inertial Sensors
- Enhancing the Performance of Pedometers Using a Single Accelerometer
I have no idea how these methods would perform in real-life applications or how to turn them into a nice Android app.
A similar question is Calculating distance within a building.
For some other interesting reading on emerging indoor positioning technologies, check out this blog post from Qubulus. There are several startups and research projects trying to find a good replacement for GPS indoors. Attempts range from Dead Reckoning, to QR Codes, to light pulses, to radio fingerprinting. It looks like any viable solution will combine multiple technologies (similar to how most smartphones rely on A-GPS, where the satellite signal is assisted by cell tower multilateration).
Best of luck with your application!