I am writing a program in Android that uses GPS. It will prompt the user to turn on location services if it is not on (which I guess is equivalent to turning on gps ?). My question is: does the gps immediately start consuming extra battery power as soon as location services is turned on or it uses batter power whenever the location services is queried/used for a new location ?
The GPS starts working only when the location manager requests an update from it. Turning on the GPS in the device only allows programs to request locations if they want, but it doesn't mean the GPS is kicking in.
You can test it yourself: The GPS icon in the notification bar tells the GPS status. You can turn on the GPS, but the icon won't appear. Why? No application requests updates now. As soon as an application requests an update, the icon starts blinking (The GPS is initializing itself) and when it stops, it means the GPS is initialized and is currently receiveng updates. The GPS consumes battery only when this icon appears.