Nokia tracker

This is idea for GPS tracking device. A few days ago, I read about a missing children and I came up with the idea for Nokia GPS tracker. It will be a small device that can be hung anywhere. I have made only housing for the device, to see how it would look like. And how would this work: this device will be connected with application on Lumia, and on Lumia you will see a position of child or dog, etc. Please give a suggestions, and opinions. B) http://en.wikipedia.org/wiki/GPS_tracking_unit http://en.wikipedia.org/wiki/Radar_tracker http://en.wikipedia.org/wiki/GPS_tracking_server