https://en.wikipedia.org/wiki/GNU_Radio
@neauoire Yes, I was aware, but like so many tech things, the more involved you get with this stuff, the more you realise just how little you actually know. Which for me is GREAT.
SOmetimes mainstream stuff at sea is good. I only recently realised just how awesome AIS was, as I sailed across the Dover straits. with 450 ships in view. Unless you can really get odd software projects to help you then no amount of belief in 'open source' is actually going to help you.
@neauoire Oh, if you have NMEA running on board, than you can suck data from AIS and plot it straight into OpenCPN. I don't know if Navionics does this, but it will definitely work on OpenCPN. It's amazing seeing your plotter with all these big ships on it. Not a big deal in Tonga, but around the straits of Dover, it's seriously helpful. ;)
I shall leave you as I have to go. Best Jonathan.