Very interesting--although still not available, and I've heard that phrase too many times over the years, with too many years of "next quarter" promises.
It sounds like they are using a very highly integrated GPS
and low-power burst mode transceiver, the equivalent of SMS messaging on cell phones but restricted (?) if I read it correctly to essentially sending a short selection of messages, i.e. "OK" "Mayday" and perhaps whatever else fits in a 1-bit sigal flag on their burst?
SMS has been incredibly profitable for the cell phone
companies (one data packet on the "empty" signal channel, selling at something like 1000x the price
of data packets on the voice channels) maybe this will work
out very nicely!