“enhance the usability of location-aware system� as a very abstract goal. This might need to be reformulated

Usability is a very abstract and individual thing, however one of the most important things. I have done resarch in the field of “Mobile Government” and especially application design in the public sector. And one of the key issues was (and probably is) user experience vs user expectation. And the usability (services and applications) plays a major role on the road to broad user acceptance.
Wherever your paper is headed, you most definitely need to reformulate … waiting to see more results, l like your research subject and would like to exchange on the results.