I had the pleasure to be external examiner for the PhD thesis of Ulrich Steinhoff at the Technical University of Darmstadt. Ulrich did his PhD with Bernt Schiele and looked at different location techniques. From my perspective his work on dead reckoning for mobile devices that are NOT fixed to a specific position on the body .
There are always suprises at PhD defenses ;-) and the positive one at this one was a cake in the shape of a doctoral hat.
 U. Steinhoff and B. Schiele. Dead Reckoning from the Pocket - An Experimental Study. Eighth Annual IEEE International Conference on Pervasive Computing and Communications (PerCom 2010). http://dx.doi.org/10.1109/PERCOM.2010.5466978