Or that was the initial concept. You can track a phone's location via sms and you have the option for encryption, so your location won't leak here and there.
Get it from:
https://play.google.com/store/apps/details?id=com.vaslabs.trackpa
Receiver:
https://play.google.com/store/apps/details?id=com.vaslabs.trackpa_receiver
I would have the receiver free as well, but I have to use google maps API service, so this is mainly to avoid spam and api charges or cover them if the need arises. You can get it for free by compiling the source code (see below) using your own API keys.
Source code:
https://github.com/vaslabs/trackpa
https://github.com/vaslabs/trackpa_receiver