Interfacing AIS

[tonyappuk]

I have searched the site but I can't find details of how to connect a suitable receiver to my PC/laptop to show AIS positions and data. I have been trying to use a sound input USB dongle but with no success. It's possible it is faulty but I can't definitively test it. If the PC or laptop has a sound input jack or dongle is it just a question of plugging in from the receiver and selecting that as the AIS source in OpenCPN? I'm sorry if this is covered elsewhere (the help file is incomplete for AIS) but I would be grateful if some kind soul could help me.
Tony

[donradcliffe]

You mght start here ShipPlotter FAQ File

[tonyappuk]

Thanks for your response donradcliffe but it doesn't really help me to get OpenCPN working with AIS. I understand what AIS is and I have a modified receiver with discriminator output that I want to use with OpenCPN. I have looked at most of the links you suggested many times before and I'm still not clever enough to get it working.
Tony

[cagney]

Check this thread for the missing linkImproved GNUAIS (AISMON for Linux)

Thomas

[tonyappuk]

Cagney, thank you too for your response and link. Unfortunately it doesn't really help. Otya points out that, in a linux environment you are offered ttyS0-3 and I have tried them all as well without success. How would I identify which is the right one? More importantly I am more familiar with Windows and my Linux abilities are small. Consequently I'm looking for a guide to getting the Windows version working. I'm sure someone can give me a step by step procedure. Please assume I'm an idiot!
Tony

[Pegase]

Tony,
Did you test your equipment with Shipploter ?
If you are sure that everything's fine, do it like this :
Download AISMON : aismon : AIS_Monitor
Then install one pair of emulated COM port (explained in the help file of AISMON)
Set output of AISmon on one emulated port and OpenCPN (AIS tab) on the other one.

After it should work perfectly.

[tonyappuk]

Thanks, Pegase. I think that's what I need. I shall download aismon and experiment on the boat next week.
Tony

[tonyappuk]

Pegase
Unfortunately still not working. I have installed Aismon and it apparently sees something from my sound card (Realtek), but not consistently. You mentioned the help file in Aismon but I do not see one in 2.2.0. On the links section of the Aismon Yahoo group neither of the links to the emulators work. I would be grateful for pointers to other sources or indeed more direct help. I can set Aismon to output NMEA to a comm port and direct Opencpn to connect AIS to that port but it does not work. I would be very grateful for more help please.
Tony

[otya]

Originally Posted by tonyappuk

Pegase
Unfortunately still not working.

Seems you are getting as frustrated as I was. Without looking back on my posts I too had trouble decoding and not much success with 2 different radios tried with taps into the discriminator. I did manage to decode a few intermittent transmissions line of sight from about 4nm away thru the soundcard - and that was it!

I never got to the bottom why I had so much trouble and others seemingly didn't. Anyway I gave up and recently purchased a nasa3 engine (89GBP not the asking ~$600 here in Oz). Whilst I will again pursue the soundcard route later there is one big advantage in having the nasa. It is standalone and can be left on all the time without much current draw. It should act as a good alarm without the laptop(that is when I connect a buzzer to the msg received green led indicator).

Some have mentioned using a high end sound card but the bog standard one in laptop inbuilts should be up to the task (generally capable of sampling at44kHz of a 9600b ais signal should be OK) If the radio IF freq is off that also might confuse the gnuais algorithm. It seems that the gnu algorithm also may not be the most effective anyway -but it does work as attested by others. The difficulty is finding out where the failure point is: antenna- radio- tap - -soundcard- decoder. Using a oscilloscope is not much use as the ais signal is buried in the noise.

Anyway hope you have better luck than I had

[Pegase]

I think you have to proceed step by step.
You seems to have several problems and we don't know what's working.

Step 1 : check software. on the Aismon forum there is a .wav file that you can use to check the software setup. Several AIS target should appear near the US coast. If not you have a config problem that you have to solve. With emulated com port I had to setup n° 7 and 8 as my old computer doesn't accept higher number than 8.

Step 2 : Now that we are sure that software is working try again with your modified receiver. Try also to run you laptop only on batteries (not AC power) to reduce noise. You might also check ShipPlotter FAQ File that your soundcard meets the minimum requirements.

For the emulated com ports try make a search on Internet (key word comemuldrv). There is a lot of available help. first link Setting up Virtual Serial Ports

Be patient ank keep trying . It's gonna work

[tonyappuk]

Pegase
Thanks for your further thoughts. I have made some progress and I'm optimistic that next time I'm down on the boat at the marina I might see good things. I still can't see a help file in AISMON but I have done the usual Googling and found some assistance. I also managed to find a link to the com ports emulator driver. That's now installed and set up but it needs a trip to be near ships to prove it's working. Unfortunately the English Summer is upon us and so of course it's raining and blowing a hoolie. I'll post again soon.
Tony

[tonyappuk]

Further to my problems in interfacing AIS into Win Xp I have now succeeded. Pergase, you set me on the right track and today at long last I can see AIS data and targets.
I promised myself I would faithfully record all the steps I took to succeed but as we all know good intentions fly out the window when you are getting frustrated.
Some of the things I discovered.
The mono sound jack to USB convertor bought on Ebay using the Prolific drivers did not work. This seems to be a common complaint.
The mod to provide a discriminator tap as set out on Discriminator Output works well and has a wealth of information. I am using an old Realistic Pro 50 scanner bought from Tandy's years ago.
The AISMON Yahoo group is another valuable source of information although some of the offered links are dead. AISMon_2.2.0.exe is OK though and you will need it.
AISMON gets its input from your PC sound card. In my case my old Thinkpad T40 uses a Soundmax card/chip which works OK.
You will also need a virtual com port program and ComEmulDrv3 is offered on the Yahoo group but this link is dead. I Googled around and found it at http://www.mixw.net/files/ComEmulDrv3.zip. You will need this to set up a pair of virtual com ports to connect the output of AISMON to AIS in on Opencpn. I used Com 7 and Com 8
If anyone else is having problems perhaps I can help but in any case my thanks to all those here who helped me succeed.
Tony

[kiwiradical]

Eterlogic has a very useful freeware virtual com port application, as well as many other options it provides splitter ports. Eterlogic - VSPE: tool for serial ports emulation

I've used it for AIS, and for allowing multiple applications to connect to a GPS NMEA stream.

[richardhula]

Check out NavMonPc - this FREE program offers boat instrument & AIS display & has optional virtual port driver installation for sharing data within your PC or sending/receiving it over TCP/IP.