Google location services
This setting enables or disables Google location services, which determine your location using Wi-Fi and mobile networks. This setting controls two things:
- Whether apps may make use of Google's location services. The location obtained from this service is often significantly more accurate than using mobile cell location alone as it can determine location from the existence of nearby Wi-Fi access points and match that against Google's knowledge of where these access points are. In case no Wi-Fi access points can be found, or at least there are none that Google knows the location of, the location of your mobile cell tower can be used.
- Whether Google may collect information about your location in the background, including while the phone is asleep, in order to improve its services. Google may occasionally activate your GPS receiver in the background to get an accurate location, and use this information to send the location of nearby Wi-Fi access points to Google to improve its location services.
Unfortunately it is not possible to have one without the other: if you don't want Google collecting information about your location and using it to improve its location services, you can't use Google location services to get a fast and reasonably accurate location in apps.
Note that Google's collection of location data in this setting is intended only to improve their location services and not to link your Google account to your location.
Despite having a reputation for being a battery hog, Google's location services should only use a small amount of battery power, especially in recent versions of Android (4.2 and higher). Its reputation probably comes from the relatively large amount of time it spends keeping your phone operating while its screen is off, even though its CPU utilization is not high during this time. If you are very concerned about CPU utilization while your device screen is off, you can consider disabling this service.