Android Inertial Navigation

We require a simple Android app that will take a starting point on a map (either from GPS or user selected from Google maps) and then using only the sensors in the phone (gyroscope, accelerometer, magnetometer, barometer (if present)) estimate the current location of the user on the map (latitude and longitude). GPS will be recorded for comparison but must not be used to calculate the position (other then the start point) and may be turned off at any time. For each second the path must be plotted on the map and the coordinates saved to a log file. The application is for pedestrian navigation so it must support variable walk speeds, step lengths and complex navigation paths. It should support walking and running as well a long periods of non movement. Efforts makes be made to eliminate (or reduce) the effects of sensor drift. Expected accuracy is within 2% of the distance traveled in order to pass acceptance. Full documentation, executables and source code must be provided.