Location Based Services

Modern mobile phones store geographic information, GPS coordinates, wifi networks, mobile cells.

IOS

• Stores wifi networks:
  • BSSID, Location, Accuracy, Timestamp, ...
• Stores mobile geo information:
  • your providers cell towers, Cell Numer, Location, ...
• Database without size limit
• Sends data how?
• Correlates with GPS
• Data used ..?

Android

Android's location services stores information for caching reasons in two database files to speed up your GPS fix.

Information stored

Location on your device

• /data/data/com.google.android.location/files
  • cache.wifi
  • cache.cell

Database

• Database is limited to:
  • 200 Wi-Fi entries
  • 50 Cell entries

Value	Type	Description
key		cell: mcc + ":" + mnc + ":" + lac + ":" + cid Wi-Fi: BSSID
accuracy	int
confidence	int
latitude	double
longitude	double
readingTime	long

Settings

• Settings -> Location & Security -> Use wireless networks
  • when ticked: stores information in two databases
  • when un-ticked: no information get's stored on your device

• 

  Location Settings

• 

  Google informs you that they will use your information

How to disable the cache

There are two ways to "disable" prevent your phone from storing caching information on your device.

First method

Your can disable the whole caching process by un-ticking Use wireless networks under Settings -> Location & Security -> Use wireless networks. But this may slow down your GPS fix.

Second method (requires a rooted phone)

You can prevent that the location service writes to the said two files with

• chmod 000 /data/data/com.google.android.location/files/cache.wifi
• chmod 000 /data/data/com.google.android.location/files/cache.cell