I'm going to make an app similar to Pokemon Go.

I'm going to make an app similar to Pokemon Go (only Android), and I have a question about the functional plan.

When I downloaded the app -> GPS On -> and went to a specific location (I'm expecting an error range of 5 to 10 meters), the push alarm on my phone "Here it is! " "

I would like to proceed like this, is there a library provided by Google??

Please let me know if you have, it doesn't matter if it's paid/free!