I presume that your worry is abduction. If that is the case then a GPS tracker would take you to the correct building, but not inside it.
Check this site out.
http://www.brickhousesecurity.com/gps-c ... gging.html
This is something that has been on my mind for some time now, as I have a 3 year old son who is far too adventurous for his own good. I lost him at Mustafa centre the other day with people packed to the rafters.. Let us just say that I did some rough jostling and made few friends before I found him again.
The solutions that my cursory search rooted out seem to be expensive, with the main expense being the monthly subscription to the tracking service. I don't think the site above, or any that require a monthly subscription is optimal or necessary. The GPS device itself is very small and the bulkiest part would be the battery and mobile device capable of sms communication. All it need do is send coordinates to a GPS capable phone for tracking.
Ideally however the device should also include a short range tracker (<500ft) that could be used to narrow in on an indoor target.
I do not think that this product is available.
The nature of Monkey was ... irrepressible!