The problem is integration drift. I don't think it's really feasible to do inertial navigation with a smartphone. The paper you linked is also discussing use o

The problem is integration drift. I don't think it's really feasible to do inertial navigation with a smartphone. The paper you linked is also discussing use of WiFi and Bluetooth. Edit: here's a good overview: http://stackoverflow.com/a/7835988 http://stackoverflow.com/a/7835988