Yes. A patent, not copyright
. I am not a native speaker and sometimes mix up words and meanings from my other languages.
Vesper does have the pre-calc or pre-vis mode. Why others do not is a riddle. OpenCPN
has an even better pre-vis mode, but Open is not a $$$ hardware
sold by "big companies" it is just a free
piece of software
written by keen individuals. Makes one think what takes the "big companies" so long.
As for 'ack' msg - it is a transmit and forget approach
but the protocol is of broadcast type and so it does not preclude requests and confirms (as exemplified by sentence types 6 and 15).
I am just one silly head
. I think anybody who is a pro can look at the specs and find half a dozen of features that could be easily implemented to make our sailing lives (even) safer.
Not that the system is bad. It is good. Just it could be twice as good.
A Fiat is a good car. Just that a Ferrari always seems faster.