that means GPS location is on. you can change that to E911 only under "location settings" and the 3 lines will disappear, but the target picture will stay on.
if you have an app that uses the GPS to help find your location, than you may want to leave that on. if not, for instance, google maps will ask you everytime you start the app to turn the gps on. it's kind of like wifi, if you're using it, leave it on, but when you're not, turn it off.
