What's a good Android app for keeping tabs on my grandkids without being all up in their business 24/7?

Look, I'm not trying to be Big Brother, but with the grandkids running around, it's good to have some idea where they are. This Family GPS Locator app, it's actually rugged. I mean, I accidentally left my phone out in the rain the other day, and it didn't even blink. The app still worked fine. It's built like a brick house, this thing. The location tracking seems pretty accurate, too. Not pinpoint, but close enough to know if they're at the park or wandered off to the candy store again. The tutorial is useless, but once you figure it out, it's straightforward. No BS. Only real complaint is the battery life. Seems like it drains faster with the GPS running constantly. Gotta remember to charge it every night. Still, it gets the job done, and that's what matters.