TV-GPS is the latest GPS related acronym. TV-GPS is a newly proposed system by Rosum for determining location. Instead of using GPS satellites roaming the skies the TV-GPS piggybacks on existing commercial TV broadcast signals. The system promises reception to be exceptional, including indoors. (Most people do watch TV indoors.)
There are a few other subtle differences too. With traditional GPS, the location calculations happen on the GPS receiver itself. Whereas the Rosum TV-GPS solution requires an intermediate “Location Server” to assist the processing.
I suspect there are a few other limitations as well. For example what about rural areas where over the air TV signals are non-existant? Due to the commercial infrastructure and the necessary “location server” TV-GPS wouldn’t likely be “open” like the current GPS system is and would probably require a subscription.