[gears-users] How get user's location using nearby cell-tower

[Forgetmiss]

Hi,
  I want to get location using nearyby cell-towers,
1 But I find the Geolocation API seems automatic get  location ,Is
it?
2 How the API determine your location using nearby cell-towers or GPS
for your mobile device or your computer's IP address ?3 Can I  appoint
cell-id to make the API get location by cell-tower? How I do?