Understanding User Notifications UNLocationNotificationTrigger Swift

Hi, I need to send a user notification when the user enter a certain location/region. I noticed that there is a UNLocationNotificationTrigger class to do just this insed the UserNotification framework. I have a little experience using User Notifications with time intervals but haven’t used the trigger by location. I have a couple of questions when using UNLocationNotificationTrigger.

1.      When you set a user notification by location, does that means that the phone will constantly be searching the user’s location, or the GPS will automatically trigger the notification when the user enters the designated location without constant searching?

2.      Does UNLocationNotificationTrigger drain the phones battery?

Thanks