AIS receiver, UBS dongle

[Maelruan]

AIS Catcher stops with a message that RTL_SDR has timed out after about an hour, when used with OpenCPN 5.8.4, Win 10, RTL SDR Ver3 dongle. This happens both when AISCatcher is run seperately from OpenCPN or when incorporated into the rtlsdr plugin in the manner show in mickey YT9TT's You Tube video. This did not happen when tested ashore with far less AIS incoming messages. There is a device specific setting "TIMEOUT [1 - 60]" with AISCatcher instructions for use with the -gt switch for RTLTCP devices (rather than -gr for RTLSDR's) which might be causing the problem.

[mickey_YT9TT]

I finished writing the installation guide. It could be on install page also, I have it as .pdf

I will divide this tutorial in 4 sections so you can skip parts you know or already have set up before.
For following this guide, it is necessary to have an RTL-SDR receiver (V3/V4 would be preferable or any other with TCXO nooelec, Shipxplorer etc.), antenna tuned to 162Mhz and a computer with Windows (tested on 10/11)
You can also use other but much more expensive receivers e.g., AirSpy (Mini/R2/HF+), HackRF, SDRPlay RSP1A etc. Settings are bit different for those type of receivers and they can be configured in step 12, everything else is same.
Installing drivers for RTL-SDR dongle and calibrating (if necessary)

I will not cover this section in detail as that is more than enough explained in this blog page https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/. 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 https://cognito.me.uk/computing/2015...ld-32-bit.html and once you finish, write it down rounded value in PPM as you will need that later.
If you don’t want (or can’t) use kalibrate, you can set 0 for PPM value if you are using V3 / V4 RTL-SDR blog receiver, most likely that would be the closest value.
Installing OpenCPN

Download latest OpenCPN program if you don’t have it already installed, else you can start from step 3.
1. From website https://opencpn.org/OpenCPN/info/downloadopencpn.html download latest version, currently it is 5.8.4. It must be 5.8+ because it is different procedure for 5.6.X version.
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 decoder first.
3. We must prepare folder where decoder will be installed. 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
4. Create folder rtlsdr_pi then open it, and create another folder bin. Windows might ask aboutrights, just confirm that you want to create those folders and leave bin folder open. This is case sensitive so be careful.
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, but it is one time only type of settings.
5. From Jasper’s github page https://github.com/jvde-github/AIS-catcher/releases latest version is v0.55 and because my Windows/PC is x64 I will be downloading AIS-catcher.x64.zip
6. Unzip files and copy all 13 files + 2 folder to bin folder that you left open in step 4.
7. Rename AIS-catcher(.exe) to rtl_ais(.exe) this part is essential, because plugin only “see” rtl_ais
Installing plugin for OpenCPN to communicate with decoder/RTL-SDR receiver

8. Now, run OpenCPN. Plugin is not visible or disabled by default. Go to gearbox (if you don’t see it click hamburger button)
9. Go to Plugins tab and in bottom left click on Update Plugin Catalog: master, wait for update successful message and close pop-up window.
10. In the list search for rtlsdr 1.4.7.0 clickon itand in new window click Install. Plugin will now be at top of the plugin list, search for it and click on Preferences.
11. On first drop-down list AIS should be selected, on second (Program) select rtl_ais. If you don’t see rtl_ais in drop-down list, recheck steps 3-7.
12. 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
13. In Error Correction field enter PPM value that we calculated in the beginning then click OK to close small window and hit Apply*.
14. Stay within Options window of OpenCPN and go to Connections.
15. Next, click Add connection to setup where decoder will be sending UDP packets.
16. In Configure new connection check Network, protocol is UDP; Address is 127.0.0.1 and DataPort is 10110. Control checksum and Receive Input on this Port should be 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 receiver first.
*If pop-up window with System error appears with a message VCRUNTIME140_1.dll not found, then install Visual Studio runtime libraries (https://docs.microsoft.com/en-us/cpp...?view=msvc-170)

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 12. One of them offers activation of internal webserver so you can also monitor vessels on web browser, plot them on OpenStreetMap (NOAA nautical charts as overlay too) and show other advanced info, comprehensive statistics, own plugins and other. Add -N 8100 at the end of other parameters, restart decoder, uncheck and recheck Enable box in step 17 (you might see firewall complaining, just allow operation of it). Open your browser and type 127.0.0.1:8100 and you will see 5 tabs, Summary; Plot; Ships; Map; NMEA. You can also experiment with antennas, gain settings, and data feeding to sites like shipxplorer, vesselfinder, marinetraffic etc.
If you don’t have any charts installed in OpenCPN, find local authority that can provide them for your region.

[JBP]

Thanks.
I saw someone's testing of ShipXplorer vs RTL-SDR and they found that ShipXplorer did slightly better for the purposes of AIS since it was tuned strictly for AIS?

[mickey_YT9TT]

Originally Posted by JBP

Thanks.
I saw someone's testing of ShipXplorer vs RTL-SDR and they found that ShipXplorer did slightly better for the purposes of AIS since it was tuned strictly for AIS?

"Generic" dongles as well as V3 and V4 have open front end so they can tune from 500kHz to 1,7 GHz and that is good and bad thing at the same time. They can be easily be overloaded from strong broadcast FM/GSM/similar signals so they can become "deaf" for low power "burst" signals as AIS. So ShipXplorer followed design from ADS-B dongle and they built-in SAW filter marked 395 and low noise amplifier chip PSA4-5043+ to compensate filter losses and to further amplify signal.
In my tests, ShipXplorer dongle had 30% more message rate and range was waaay better.
Anyhow, I also experimented with antennas which is also important but eventually ShipXplorer had better results. All tests were inland so bear that in mind. In this kind of scenario I only see advantage of unfiltered receivers such as V3/V4/nooelec or other expensive ones is that you can listen to VHF marine communication if you are not decoding AIS signals which you can't do with ShipXplorer dongle.
I'm not an expert in marine stuff in anyway but I am still learning.
Sorry if I have typos, English is not my native language

[rgleason]

mickey_YT9TT I just saw your posts and instructions. I've been away for awhile and have a lot to catchup, but will get to this. Please remind me in 3 weeks if I haven't updated the manual. Thank you!!!

[JBP]

Awesome. Thank you both. I'm planning on getting a ShipXplorer next season because I'm hoping to do some overnight passages on Lake Erie and being able to keep an eye on any freighters intent on running me over will make me more comfortable. (Plus it's a new toy to play with).

[rgleason]

Originally Posted by mickey_YT9TT

I finished writing the installation guide. It could be on install page also, I have it as .pdf

I will divide this tutorial in 4 sections so you can skip parts you know or already have set up before.
For following this guide, it is necessary to have an RTL-SDR receiver (V3/V4 would be preferable or any other with TCXO nooelec, Shipxplorer etc.), antenna tuned to 162Mhz and a computer with Windows (tested on 10/11)
You can also use other but much more expensive receivers e.g., AirSpy (Mini/R2/HF+), HackRF, SDRPlay RSP1A etc. Settings are bit different for those type of receivers and they can be configured in step 12, everything else is same.
Installing drivers for RTL-SDR dongle and calibrating (if necessary)

I will not cover this section in detail as that is more than enough explained in this blog page https://www.rtl-sdr.com/rtl-sdr-quick-start-guide/. 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 https://cognito.me.uk/computing/2015...ld-32-bit.html and once you finish, write it down rounded value in PPM as you will need that later.
If you don’t want (or can’t) use kalibrate, you can set 0 for PPM value if you are using V3 / V4 RTL-SDR blog receiver, most likely that would be the closest value.
Installing OpenCPN

Download latest OpenCPN program if you don’t have it already installed, else you can start from step 3.
1. From website https://opencpn.org/OpenCPN/info/downloadopencpn.html download latest version, currently it is 5.8.4. It must be 5.8+ because it is different procedure for 5.6.X version.
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 decoder first.
3. We must prepare folder where decoder will be installed. 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
4. Create folder rtlsdr_pi then open it, and create another folder bin. Windows might ask aboutrights, just confirm that you want to create those folders and leave bin folder open. This is case sensitive so be careful.
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, but it is one time only type of settings.
5. From Jasper’s github page https://github.com/jvde-github/AIS-catcher/releases latest version is v0.55 and because my Windows/PC is x64 I will be downloading AIS-catcher.x64.zip
6. Unzip files and copy all 13 files + 2 folder to bin folder that you left open in step 4.
7. Rename AIS-catcher(.exe) to rtl_ais(.exe) this part is essential, because plugin only “see” rtl_ais
Installing plugin for OpenCPN to communicate with decoder/RTL-SDR receiver

8. Now, run OpenCPN. Plugin is not visible or disabled by default. Go to gearbox (if you don’t see it click hamburger button)
9. Go to Plugins tab and in bottom left click on Update Plugin Catalog: master, wait for update successful message and close pop-up window.
10. In the list search for rtlsdr 1.4.7.0 clickon itand in new window click Install. Plugin will now be at top of the plugin list, search for it and click on Preferences.
11. On first drop-down list AIS should be selected, on second (Program) select rtl_ais. If you don’t see rtl_ais in drop-down list, recheck steps 3-7.
12. 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
13. In Error Correction field enter PPM value that we calculated in the beginning then click OK to close small window and hit Apply*.
14. Stay within Options window of OpenCPN and go to Connections.
15. Next, click Add connection to setup where decoder will be sending UDP packets.
16. In Configure new connection check Network, protocol is UDP; Address is 127.0.0.1 and DataPort is 10110. Control checksum and Receive Input on this Port should be 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 receiver first.
*If pop-up window with System error appears with a message VCRUNTIME140_1.dll not found, then install Visual Studio runtime libraries (https://docs.microsoft.com/en-us/cpp...?view=msvc-170)

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 12. One of them offers activation of internal webserver so you can also monitor vessels on web browser, plot them on OpenStreetMap (NOAA nautical charts as overlay too) and show other advanced info, comprehensive statistics, own plugins and other. Add -N 8100 at the end of other parameters, restart decoder, uncheck and recheck Enable box in step 17 (you might see firewall complaining, just allow operation of it). Open your browser and type 127.0.0.1:8100 and you will see 5 tabs, Summary; Plot; Ships; Map; NMEA. You can also experiment with antennas, gain settings, and data feeding to sites like shipxplorer, vesselfinder, marinetraffic etc.
If you don’t have any charts installed in OpenCPN, find local authority that can provide them for your region.

Please see this page https://opencpn.org/wiki/dokuwiki/do...ardware:rtlsdr

This page will be improved and edited. Its location is temporary.
If there are screenshots and images, they can be included. Thanks.

[JBP]

Thanks. I did get a ShipXplorer and it works just fine on Android. Ais-catcher immediately recognized it as a RTL-SDR device, captures the AIS dara and sends the AIS data to a udp port. OpenCPN received the AIS data from the udp port.

[bcn]

How do you resolve charging of the Android device as the USB port is used by the dongle?
In general the Androids do not allow for parallel USB devices and charging through the same and only port - there are few exceptions though. For example a Pixel 3 will allow wirless charging and a dongle at the same time.


Hubert

[JBP]

I haven't yet. I've seen "Y" USB OTG cable specifically designed to solve that problem or maybe use a wireless charging pad.

https://www.walmart.com/ip/JSER-USB-...f1c8&gclsrc=ds

https://www.ebay.com/itm/35530635761...0d12c2e8aa5f04

https://www.amazon.com/Adapter-Femal.../dp/B08KPD5S82

[bcn]

It's not just the question of an Y-cable. In the fine print of the cables offered there is usually a very short list of devices that shall charge when using an OTG device.

[JBP]

Why is that? Why would some USB devices not accept power? I'm thinking that amazon one should be OK since it supports Quik Charge for the USB C device and I'll probally be using a USB-C device.

I've not yet decided how I'm going to use it. Do I just want one device that shows AIS data? Do I want to share it on my NMEA network? I think a dedicated device like a raspberry pi is way overkill for my purposes.

[JBP]

Ah, here is some info.
https://android.stackexchange.com/qu...charging#34234

https://android.stackexchange.com/qu...harging#157895

[JBP]

Ha! Someone else doing exactly the same thing. I'm guessing that it will work with my Samsung phone and tablet but maybe not on my el-cheapo tablet. At least enough to risk $10.99 on one.

[Maelruan]

Further to my post #16 above, I have now followed the new download and installation instructions from mickey_YT9TT and RGleason, and AIS-Catcher seems to be working much better! It has been running for almost 7 hours now without the timeout problem previously experienced. Many thanks, and Happy New Year!