FamilyGuard is an app that helps parents to track location of there kids via continuous geo tracking. Kids will be able to send panic alarm, pick me up, or a custom message. By opting premium subscription parents can also set area boundaries such as home address, school address, sleep time, and area boundary by settings these area boundaries parents will be able to receive notifications if any of the kid crosses the area boundary outside the specified time limits.
Disclaimer - Continued use of GPS running in the background can dramatically decrease battery life.