There seem to be moreand more of these coming on the market these days. for example,
http://www.sealinks.net/SL161RPage.htm
It sounds as if this one has special software to pull all the data from an AIS signal, and GPSNavX is not mentioned as having been tested with it. I think I'll send off a note to them. Meanwhile, from their pages:
"With the addition of the embedded 12 channel GPS receiver and the optional Enhanced Signal Analysis software, supplemental diagnostic functions become available such as:
Slot Numbering
Paket Time of Arrival
Partial Packet Reception
VDL oading
Received Signal Strength Indication
Ambient Noise Measurement
The RadarPlus SL161R includes dual AIS receivers in a rugged water resistant aluminum enclosure. When attached to a VHF antenna optimized at 162Mhz, the RadarPlus serial data output will drive most popular marine charting software packages available today. The output provides the location of all AIS transponders within receiving range. Other interface options, such as USB, Ethernet, and RS-422 are available to increase the overall flexibility of the RadarPlus SL161R.
Information gathered by the RadarPlus SL161R is more detailed than radar and provides the everyday boater with the same information afforded to commercial vessels. Now you can see what's coming on your PC or chart-plotter long before it is in your line of sight.
The RadarPlus SL161R allows AIS enabled software to chart ship positions and descriptions in real-time.
The following packages have been tested and are fully operational with the SL161R:
Rose Point - Coastal Explorer
ICAN - Regulus
Transas - NaviSailor
Xanatos - Titan
Nobeltec - Admiral
EuroNav - seaPro
To request full serial interface specifications, please e-mail info@shinemicro.com or call Shine Micro at (360) 437-2503."