Attention! Does not work with newest OpenCPN 5.8.2
This is detailed (slightly different compared to the video clip) description how to install “one click” solution for decoding AIS signals with RTL-SDR on Windows PC and connect it with OpenCPN
For following this guide, it is necessary to have an RTL-SDR receiver (V3 would be preferable or any other with TCXO nooelec, Shipxplorer etc.), antenna tuned to 162Mhz and a computer with Windows 10, so, plug in receiver and let’s have some fun.
Installing drivers for RTL-SDR dongle and calibrating (if necessary)
Many of you do have it running already and I will not cover this section as that is more than enough explained in this blog page www.rtl-sdr.com/rtl-sdr-quick....
Instead, I will instruct you to check is your dongle accurate on frequency or not because these signals are narrow and will tolerate only slight frequency drift. Even if your dongle has TCXO it can initially also be slightly off but it will not drift overtime.
There is great program kalibrate or kal which will determine if SDR is spot on frequency. Follow this page to check PPM value of your dongle cognito.me.uk/computing/2015/... and once you finish, write it down as you will need that value later.
Installing OpenCPN
If you are not familiar with the OpenCPN program and do not have it installed, follow next steps, else you can skip it.
1.From website opencpn.org/OpenCPN/info/down... download latest version, currently it is 5.6.2.
2.Install it using default values for install location. At the end of install uncheck option Run OpenCPN so you don’t run It as we need to install plugins.
Installing plugin for OpenCPN to communicate with decoder/RTL-SDR receiver
3.OpenCPN has plenty of plug-ins and you can find them on their site, thanks to Rick Gleason there is one for our needs, location is github.com/rgleason/rtlsdr_pi...
4. Install it using default values.
5. If you were using default install values go to folder C:\Program Files (x86)\OpenCPN\plugins or if you have 32-bit Windows location is C:\Program Files\OpenCPN\plugins
6. Create folder rtlsdr_pi then open it, and create another folder bin. Windows might ask about rights, just confirm that you want to create those folders and leave bin folder open.
Installing AIS decoder
In previous years I was using rtl_ais as decoder because it works out-of-the-box but recently I discovered a fantastic piece of software called AIS-catcher that continues to evolve and add new features as new versions come out. It will need some tweaks for plugin to recognize it.
7.From Jasper’s github page github.com/jvde-github/AIS-ca... latest version is v0.44 and because my PC is x64 I will be downloading AIS-catcher.x64.zip
8.Unzip files and copy all 13 files + 1 folder to bin folder that you left open in step 6.
9.Rename AIS-catcher(.exe) to rtl_ais(.exe) this part is essential, because plugin only “see” rtl_ais
Now we must tweak everything to run smoothly. You can close all other folders and programs and run OpenCPN
10.When installed, plugin is disabled by default. Go to gearbox (if you don’t see it click hamburger button)
11.Go to Plugins find rtlsdr 1.3 click Enable then Apply and click on Preferences.
12.New window will pop up. For Program select rtl_ais in drop down list
13.In Error Correction field enter PPM value that we calculated in the beginning.
14.In extra_args field we can enter multiple values (see AIS-catcher readme). For basic operation we need to enter -gr RTLAGC on TUNER auto -o 2 -a 192K -u 127.0.0.1 10110 then click OK
15.Stay within Options window of OpenCPN and go to Connections
16.Next, we will Add connection. In Configure new connection check Network, protocol is UDP; Address is 127.0.0.1 and DataPort is 10110. Verify is Control checksum and Receive Input on this Port are checked and finally, hit Apply and OK to close options window.
17.From left menu side, you should see tower-like icon, click on it and check Enable. In Messages field we will see that decoder is successfully executed and soon !AIVDM messages will appear as well as vessels on map. You can close that window and next time you start OpenCPN, decoder will run automatically, but you need to plug in dongle first.
At the end, I will mention other options to explore. AIS-catcher has many options, and we can enter them in extra_args field in step 14. One of them offers activation of internal webserver so you can also monitor vessels on OpenStreetMap and show other advanced info, comprehensive statistics, plugins and other. Add -N 8100 at the end of other parameters, restart decoder like in step 17 (you might see firewall complaining, just allow operation of it). Open your browser and type 127.0.0.1:8100. You can also experiment with antennas, gain settings, and data feeding to sites like shipxplorer, vesselfinder, marinetraffic etc.
7 апр 2023
