Is it possible to track someone's iphone location without them knowing?

My teenager has been sneaking out late and recently figured out how to fake their location on the built-in family app, so I need another way to keep an eye on things. I’ve read about a few different monitoring tools online, but I’m worried they’ll show a notification on the screen or drain the battery really fast. Does anyone have experience with a reliable method that runs silently in the background so they won’t realize I can still see their whereabouts?