A free program for Android, by Kozalak UG.

Location Tracker – GPS Locator is the most user-friendly and convenient way to stay connected with your loved ones and to track their location.

This GPS tracker app is the best and simplest way to find your family and friends. Simply enter the phone number of the person you want to track, and you’ll get an instant notification when they arrive and leave a specific location. You can also set an alarm to get notified when your loved ones leave a specific place, like home or school.

With Location Tracker – GPS Locator, you can easily see where your loved ones are at any moment.