Opencpn & AIS

[damosail]

Hi,I'm looking for some technical help please. As well as a Raymarine plotter ( too old to be compatible with ais overlay) I use a laptop running open cpn plotter software and cmap charts. I want to see ais targets overlayed on the screen while also using the plotter function. The Opencpn programme can overlay ais but in the settings you have to nominate an ais data comm port. Does this mean that you have to have two comm ports, one for gps data and one for ais, or will it work with the ais and gps data multiplexed throught the same port. The "digital yacht" ais, that I am thinking of buying, will multiplex gps and ais data, which it outputs at the higher 38400 baud rate. Is anyone familiar with the Opencpn overlaying AIS? Can I feed gps data and ais data to Opencpn on the laptop in one multiplexed stream?
Thanks,
Damian Sidnell & Louise Lewis, living aboard Moody 39 "Backchat", Valencia, Spain.

[muttnik]

Originally Posted by damosail

Does this mean that you have to have two comm ports, one for gps data and one for ais, or will it work with the ais and gps data multiplexed throught the same port.

In the 3.0.2 which I have, in the GPS tab of the toolbox, under "NMEA data source" there's an option for "AIS port (shared)"

[SoonerSailor]

I'm pretty sure i've used OpenCPN with multiplexed ais data in the past and it worked fine. Presenrly do it with Polar Navy software and that works fine as well.

Chip

[LJH]

I am feeding my laptop a multiplexed stream from my AIS.
Select the COM Port for the AIS under the AIS tab
Under the GPS tab select AIS Port (shared) and
under the GPS tab set the NMEA baud rate to 38400 to match your AIS output.

[meridian28]

can I just tie the wires together or do I need an actual multiplexer?

[LJH]

Originally Posted by meridian28

can I just tie the wires together or do I need an actual multiplexer?

Check your AIS specs. The NMEA input should be repeated with the AIS output. If your AIS has a USB connection both GPS and AIS data should be reach your laptop. You can check the stream in OpenCPN by selecting Show GPS/NMEA data stream under the GPS tab.

[damosail]

Thanks guys,you've answered my question. I had been looking through the settings options in CPN before deciding on which AIS unit to buy, but I didn't notice the option under the gps data tab: AIS port(shared). No worries now, I'm off to buy my AIS. cheers.