April 19, 2024  AIS Weather Data

Update for all gateways with NMEA 2000: NMEA 2000 Wi-Fi Router and Gateway, Ethernet Gateway, USB Gateway and NMEA 0183 Gateway. Includes weather data, new Web Gauges and other cool features.

Coastal Explorer with AIS weather data

Formally speaking, AIS message #8 is capable of transmitting various types of data: data on navigational hazards, fairways and VTS, text messages and much more (see the list!). However, the maritime industry is very inert, and message #8 has not been widely used, despite the fact that the meteorological data format was proposed 20 years ago, in 2004.

Simrad NSX and GO7 multifunction displays, Garmin Echomap and Raymarine Axiom with the latest firmware failed to show our test NMEA 0183 and NMEA 2000 messages. However, NMEA 2000 PGN 129797 "AIS Binary Broadcast Message" support is not declared in their documentation. Below is the short list to test:

     !AIVDM,1,1,,B,8>k1oKiKpB9GO>42lBPWmre0<N00,0*55
     !AIVDM,1,1,,B,83aDChPj2d<dL<uM=hhhI?a@6HP0,0*40
     !AIVDM,1,1,4,B,8>jR06@0Bk3:wOli;<`WPhh<1rqVBQf2V@Pdt0J82avIM2b<<Rv1t<ot=@1,2*56
     !AIVDM,1,1,1,B,8>h8nkP0Glr=<hFI0D6??wvlFR06EuOwgwl?wnSwe7wvlOw?sAwwnSGmwvh0,0*17

OpenCPN developers have not yet released a version with support for this message, but the work is in progress. Expedition 10 does not fully support meteorological data, and only Coastal Explorer (see image above) was able to display data from an already obsolete message (DAC=1, FI=11, proposed in 2004, obsolete in 2013), but modern messages (DAC=1, FI=31) are not yet supported.

On the one hand, it's great that support for these messages is starting to appear in software products. But on the whole it is very sad that such a simple and powerful channel of navigation and weather data transmission is not used now, and that major electronics manufacturers are in no hurry to support it. Nor have they supported Navtex, still very popular in European waters: the latest MFD to support it (Raymarine Widescreen) has been out of production for about 10 years.

In all our products that support data conversion between NMEA 0183 and NMEA 2000 (mentioned in the header), we have added AIS #8 bi-directional message conversion. Hopefully in the coming years there will be more and more places on the planet where mariners can get useful data using it, and support for it in software products will get better and better.

Substring replacement and incoming XDR

Figure 1. Substring replacement and incoming XDR

Last December we added the ability to replace substrings in NMEA 0183 messages and correct or add a checksum to our NMEA 0183 Wi-Fi multiplexers. In the firmware update for the NMEA 2000 Wi-Fi Router, we have also added these features.

They can be very useful, especially when connecting external sensors that use the XDR sentence. Suppose you have two sensors sending fuel level data in tanks in the same messages and connected to NMEA 0183 ports of NMEA 2000 Wi-Fi Router:

     $IIXDR,V,15,P,FUEL*56

Since the sensors have the same sensor name (FUEL), it is the same data for our device. But we can change the name of the sensor connected to the first port from FUEL to FUEL_BOW, and then in the settings of the incoming XDR specify that this is our fore tank, and the remaining tank is aft.

Many of our devices have a tunnel function where incoming NMEA 0183 data is sent to another port without checking. If it is enabled, the units will also attempt to extract even incomplete data from incomplete messages and convert them. This is partly to support the early NMEA standards (even though they have been obsolete for over 30 years now, with the release of NMEA 0183 2.0 in 1992), partly to pass non-NMEA compliant string data between ports (e.g. Navtex receiver output).

The tunnel function was not present in the NMEA 2000 USB Gateway, as finding software that sends a message without a checksum has probably become impossible in the last ten years. However, we have added a setting that allows you to disable the requirement and checksum validation in incoming messages. To use it, give the command in service mode:

     SET CHECKSUM OFF

All products with a web interface include the updated Web Gauges. It fixes a very annoying behaviour where double-clicking in some browsers would cause the screen to zoom out, it also fixes minor bugs.

New Ethernet Gateway firmware also fixes problems with uploading updates in some browsers. And added a configuration mode via NMEA 2000, useful if you have one more NMEA 2000 gateway.

Ethernet Gateway settings in the CAN Log Viewer app

Figure 2. Ethernet Gateway settings in the CAN Log Viewer app

In the free CAN Log Viewer software you can get a list of devices on the bus and see their properties. For our products with IP interface, you can click on the "More..." button and see the current settings of the network interface.

Now, for the Ethernet Gateway, you can enter the commands in the "Installation Description 2" field (it can be done with ActiSense or Maretron software too):

     YD:IP 10.1.1.3
     YD:MASK 255.255.0.0
     YD:GATEWAY 10.1.1.1
     YD:DNS 10.1.1.1
     YD:DHCP STATIC
     YD:REBOOT

to change the network interface settings and reboot the device. The YD:DHCP command also accepts the CLIENT, SERVER, and MAGIC arguments. All commands can be run without an argument to retrieve a stored configuration value. Note that the saved network settings in MAGIC and CLIENT mode may not match the settings in use (it is shown on Figure 2), as they may be retrieved from the DHCP server.

We recommend that all users use update 1.72 for NMEA 2000 Wi-Fi Router and Gateway, Ethernet Gateway, USB Gateway and NMEA 0183 Gateway YDNG-03. It can be downloaded from the Downloads page.

 

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