You can also get a sunrise alarm clock. It starts slowly lighting the room up ahead of when you've set the alarm to so your body begins to acclimate to the light and starts to wake itself up more naturally. Then you're not startled awake when it's time to get up. I don't have one, as I just get up with the sun; sunrise is at like 4:30am in the summer here (6 something or so in the winter) so that does for me naturally, but I do know people elsewhere who claim it's never difficult to get up in the morning because of them.
With regard to fitness trackers, some of them simply determine the depth of sleep based on how little you move. I have a Moov and the sleep data is useless because I barrel-roll constantly while sleeping, even if I'm deeply out, yet I get like 5% of my night registered as "deep sleep." My partner just never moves and her data shows consistent bouts of deep sleep throughout the night. It's just a proxy for their inability to actually measure delta waves for deep sleep, so just beware you may not fit the profile of the "average user."