I have a cataloging mobile phone app (in progress) where labels are put on containers with a QR code encoding the id of the container. As I scan the QR Code I would like to get the relative (to a named point) XZY coordinates to centimeter accuracy. The Geolocation API (of the mobile app) does not have this accuracy. I think I need an external (Arduino based) sensor that gets the location at the point of the QR scan and communicates with the phone this information. I think I am looking for an IMU. Is this correct? Are there abstractions doing this sort of thing "off the shelf"? Are there any examples of the "location grabbing" and "communicating with mobile phonegap application"?
If I'm not on the right track please dont hold back...