is it possible to allow OpenCPN to connect to AIS NMEA streams over TCP/IP?

[nohal]

robeirne...
As far as I know, neither marinetraffic nor aishub (I think the 2 biggest worldwide ais sites) provides a free AIS NMEA feed. It's either paid service or free for contributors to the system. Both of them used to have it clearly described on the website (sorry, I don't have the exact URLs handy, but it was very easy to find on the sites when I was interested in it)

Pavel

[rgleason]

Sorry

Maybe try
http://liveaisworld.yachtmarine.com/LIVEAISWORLD.html

Let us know what you find out.

[nohal]

Yes of course, I forgot about Tore... He will sure explain it himself in detail if he comes across this thread, but as far as I know siitech is exactly an example of "share your data and we will give you our data for free" concept...

Pavel

[MAS3]

It is extremely unlikely to receive a datastream from marinetraffic.
Do you realize how much data they are processing every second ?
That is hughe, and it also overs a hughe part of the world.
This is also what this site is about; how to manage this kind of data in a reliable way, and they use those hobbyists and their contributions to study that.
It's a site of some maritime university, as clearly stated.
There are ports at a marinetraffic IP address you can connect to, but these are used for the contributors and are one way.
Each receiving station has its own port to send their data, that's a way to determine the source without logging in and / or keeping track of users.

[rgleason]

Possible USB Dongle for signal:
http://www.cruisersforum.com/forums/...x-97533-3.html

Look at these links for a possible USB cheap dongle
Had not thought of this option. See this thread.
Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles
Fast cheap AIS using $20 rtl-sdr DVB-T SDR Dongles !
There may be a number of SDR (Software Digital Radio) users with experience with these dongles. RTL SDR RTL2832 who can advise.

Also
http://www.cruisersforum.com/forums/...ml#post1153456

(We are looking for one which will also work for weatherfax's (which I believe needs to be in the 22mhz min range according to Sean.)

[robeirne]

Nohal wrote

As far as I know, neither marinetraffic nor aishub (I think the 2 biggest worldwide ais sites) provides a free AIS NMEA feed. It's either paid service or free for contributors to the system. Both of them used to have it clearly described on the website (sorry, I don't have the exact URLs handy, but it was very easy to find on the sites when I was interested in it)

I had reached the same conclusion. It's funny because the information is readily available via phone apps and browsers at their websites. I assumed these methods superimposed the NMEA data onto a selected map.

Anyway I think I shall give up and get a proper AIS receiver if I ever need it.

[dzhiurgis]

In regards of RTL-SDR, I wasn't able to receive AIS signal, probably because I was 30k ft high. The plane signals plotted quite well.

[MAS3]

Maybe next time you should open the window and hold your antenna outside .
The fuselage probably is made of some metal, dampening the signals quite a bit.
One might think being that far up, you'd have a quite large coverage.

[WayneB]

Originally Posted by sailorF54

Yep

Welcome to the forum...

Try these settings (they refer to the checked entry) in latest beta version for a test...

RTFM can help too... Big Question Mark on blue backgroung in the Toolbar, Help section... (BTW thanks Cagney)

I can connect ok with a UDP connection but not TCPIP. Did you have to open up a port on your firewall or anything like that? I notice in your screenprint that you specify output=no on your tcpip connection but did not understand the reason.

[muttnik]

Originally Posted by WayneB

I can connect ok with a UDP connection but not TCPIP. Did you have to open up a port on your firewall or anything like that? I notice in your screenprint that you specify output=no on your tcpip connection but did not understand the reason.

If you tried to connect to the server in sailorF54's screenshot, that's been down for at least a year:

http://www.cruisersforum.com/forums/...wn-100822.html

Above link mentions data from the baltic at ais1.shipraiser.net port 6492. This still works. For people with normal home routers you don't need to do anything magical with firewalls: you're making an outbound connection so everything should work (well, at least until something in the middle drops a NAT mapping...)

Unless by "connect ok" you meant you were actually receiving data (which I suspect not) you won't be "connected" to a remote AIS server with UDP. OpenCPN will just be sitting there waiting for data which never comes. If you want to connect to a remote server over the Internet to receive AIS data from it, you probably want TCP.

The "output on this port" checkbox for TCP connections is not entirely obvious. "output=no" is what you want for connecting to a remote AIS feed (like those mentioned) for two reasons. Firstly they're outputting data, not taking it in (as I understand it: could be wrong). More importantly though, if you check "output=yes", rather than connecting to a remote server, OpenCPN will create a server process and wait for something to connect to it. Which is not what you want in this context.

I recommend the data connections page in the fine manual:
Data Connections | Official OpenCPN Homepage

[WayneB]

Originally Posted by muttnik

If you tried to connect to the server in sailorF54's screenshot, that's been down for at least a year:

http://www.cruisersforum.com/forums/...wn-100822.html

Above link mentions data from the baltic at ais1.shipraiser.net port 6492. This still works. For people with normal home routers you don't need to do anything magical with firewalls: you're making an outbound connection so everything should work (well, at least until something in the middle drops a NAT mapping...)

Unless by "connect ok" you meant you were actually receiving data (which I suspect not) you won't be "connected" to a remote AIS server with UDP. OpenCPN will just be sitting there waiting for data which never comes. If you want to connect to a remote server over the Internet to receive AIS data from it, you probably want TCP.

The "output on this port" checkbox for TCP connections is not entirely obvious. "output=no" is what you want for connecting to a remote AIS feed (like those mentioned) for two reasons. Firstly they're outputting data, not taking it in (as I understand it: could be wrong). More importantly though, if you check "output=yes", rather than connecting to a remote server, OpenCPN will create a server process and wait for something to connect to it. Which is not what you want in this context.

I recommend the data connections page in the fine manual:
Data Connections | Official OpenCPN Homepage

Thanks for the response but I probably did not make myself clear. I am trying to send AIS data to marinetraffic.com via a TCPIP connection. I am currently doing this with a UDP connection but some packets appear to be getting lost. I've tried changing the connection from UDP to TCPIP but the packets are not getting through. I assume the TCPIP session is not being established properly but I'm not sure.

[JRM]

Originally Posted by WayneB

Thanks for the response but I probably did not make myself clear. I am trying to send AIS data to marinetraffic.com via a TCPIP connection. I am currently doing this with a UDP connection but some packets appear to be getting lost. I've tried changing the connection from UDP to TCPIP but the packets are not getting through. I assume the TCPIP session is not being established properly but I'm not sure.

UDP is "connectionless" so missed packets are to be expected. TCP maintains connection state, and will request retransmission of missing packets. Try running something like tcpdump and capturing the session. It's much easier to see what's going on. The problem may be in the application's handling, not the network connection (but that is outrageous unfounded speculation on the part of a reformed network engineer).

JRM

JRM

[muttnik]

Originally Posted by WayneB

Thanks for the response but I probably did not make myself clear. I am trying to send AIS data to marinetraffic.com via a TCPIP connection.

Although I did indeed misunderstand what you were trying to do, my response to this problem is going to be much the same as the last one :-)

Without "Output on this port" checked, the connection is one way, and not the way you want it (i.e. from the remote server to OpenCPN).

With "Output on this port" checked, OpenCPN doesn't connect to a remote server, but instead creates a server on the computer it is running on.

I don't guarantee that that behaviour hasn't changed in a recent beta. Actually I don't guarantee that I'm just plain wrong, but I don't think I am :-)

Your best bet might be to run another process which takes data from opencpn then make an outbound connection to marine traffic.

[mrm]

Originally Posted by muttnik

Your best bet might be to run another process which takes data from opencpn then make an outbound connection to marine traffic.

On Linux (and maybe MacOS?) there is netcat a 'Swiss Army knife of network connections' which will do just fine for that. No idea if Windows has anything.