问题
I need to get the mobile cell tower timing advance.
Is it possible on Android 2.3+ ?
[edit] It seems that it's not possible to retreive the timing advance... Is it possible to know the distance between the mobile and the cell and the bearing otherwise ? I suppose I can't use the Google hidden geolocation api in commercial application ;-) [/edit]
Thanks
回答1:
This is currently not implemented, and it will be a hard task because it is device-dependent.
The actual timing advance is only known by the modem, also called the baseband processor (BP). The modem is coded by the device's constructor and thus cannot be modified, and can differ between constructors and devices.
Android runs on the application processor (AP) and uses AT commands to communicate with the BP (modem). For example, Android internally sends AT commands to the modem to send SMS, receive calls, ...
The only way to get the actual timing advance would be to query the BP (with an AT command), but whether the constructors implement a specific AT command to get it is up to them. Unfortunately almost no devices implement it (only very old ones), so there is no way to get this information.
回答2:
For LTE technology there is already an access to Timing Advance values: see http://developer.android.com/reference/android/telephony/CellSignalStrengthLte.html#getTimingAdvance()
回答3:
I don't think it's a good idea to use timing advance for geolocation, since it is only relevant on GSM networks. Once the device hands over to UMTS networks, no more timing advance.
Why not use http://developer.android.com/guide/topics/location/obtaining-user-location.html ?
回答4:
If you need Antenna location you don't need Timing Advance. Then you need LAC, CID etc. which are all part of the public AOS API, and then you can query some public database for the location of these. There are dozens of Android apps that already does this. Perhaps even as an example app for Android developers. Google it.
However, GSM Timing Advance (TA) knowledge is definitely still of interest for several other reasons. So if someone know how to extract this info from the Android vendor RIL, please let us know.
来源：https://stackoverflow.com/questions/8111796/get-mobile-cell-tower-timing-advance-on-android-2-3