25 years or so ago, I worked on a tiny part of software for testing of what I think is a precursor for that mapping submersible. I did a two week project for Norwegian Defence Research Establishment to write software to let them relay scaled down real-time mapping data for debugging from the small boat tracking the submersible to land or a nearby bigger ship...
It was limited by wanting it to be cheap, so we used GSM data modems to transmit a 2400 bps stream of the map data, using a slight variation over z-modem to retransmit blocks on error, and code to reconnect and continue the transmission from the last successful block if we lost connection.
I'm sure that code was ditched many years ago, as it makes no sense with modern hotspots, but it was a fun project to work on, and I got to go out on the tracking boat when we tested it.
It was limited by wanting it to be cheap, so we used GSM data modems to transmit a 2400 bps stream of the map data, using a slight variation over z-modem to retransmit blocks on error, and code to reconnect and continue the transmission from the last successful block if we lost connection.
I'm sure that code was ditched many years ago, as it makes no sense with modern hotspots, but it was a fun project to work on, and I got to go out on the tracking boat when we tested it.