RE: DSC VHF Radios with GPS
It makes sense to do the DSC.* A simple GPS receiver chip set is down to a couple of bucks, and all that it needs to do is output lat/long.*
AIS is a simple analog modem, not expensive to implement once you have the receiver.* However, it would need a dedicated receiver, so there might not be much cost advantage over having a separate module that has a receiver and decoder and a serial output to a PC plotter.
Guess if you were doing active AIS (that is, broadcasting your own position) as opposed to monitoring only, you could share the transmitter, which might make it more cost effective.
I suppose that you could do a fairly simple non-graphical display on the radio that gave the basic information on each target of interest (bearing, speed, name of vessel, closest approach), but the real power of all that information (IMHO) is to have it displayed graphically where it's obvious where you need to maneuver in order not to be keelhauled by a cargo ship.
-- Edited by Chris Foster at 23:02, 2008-10-22