Use the Android measrdroid app learn more
..to collect interesting usage statistics like your mileage and signal coverage.
..to access raw data from your mobile device (e.g. inspect hardware details, environment sensors, and network configuration).
More information: http://www.droid.net.in.tum.de/
Google play: https://play.google.com/store/apps/details?id=de.tum.in.net.measrdroid.gui.stats