This applications allows to track GSM and WiFi network coverage by measuring signal strength and latency (ping against google.com). Client and server part are released under Apache 2.0 License, and map can be seen at http://www.neteffmon.com/
Please use carefully, it's far from being perfect.
About permissions: android.permission.INTERNET : used to send ping, open http connection (measures, upload). android.permission.ACCESS_NETWORK_STATE : used to get network status. android.permission.ACCESS_WIFI_STATE : if wifi is enabled, we will collect SSIDs in range.
android.permission.ACCESS_FINE_LOCATION android.permission.ACCESS_COARSE_UPDATES android.permission.ACCESS_COARSE_LOCATION All three above are used to be able to locate the measure.
android.permission.READ_PHONE_STATE : used to get gsm signal power. android.permission.WRITE_EXTERNAL_STORAGE : used to write produced data
Lots of improvements: signal detection heuristic, battery status tracking, new API, better handling with LTE