METS 2014: AIS MOB, Class A N2K, Torqeedo app, Wave WiFi router & more

17 Responses

  1. Howard says:

    No real technical comment..
    I wish I had your job! Getting to play & talk with new equipment and being in a position to talk to the engineers who work on this stuff.

  2. Henning says:

    I found this link for the redesigned 2015 Exmoor Wave WiFi 4G router:
    http://wavewifi.eu/blogs/news/15904560-new-4g-router-for-2015

  3. Henning says:

    Howard, it is – unfortunately – a misunderstanding that I have a job like Ben has. I have to work for money like most other people, currently helping a car financing bank change their core banking system. I do it for the money, which, just barely, allows me to finance my “boating habit” (when asked if it is expensive to have a boat, I usually reply “about as expensive as a gambling or a drug addiction”).
    But you can visit METS, too. All you have to do is claim that you work in the marine industry. Which I do – or did. This last year I was on a sailing sabbatical and therefore my occupation was “professional boat captain” – only with lousy pay 😉

  4. Ben Ellison Ben Ellison says:

    David Sheekey, Product and Approvals Manager at Ocean Signal wrote this:
    “Thank you for the coverage of the rescueME MOB1. It received a very good reception at METS from the visitors. To clarify, for the USA the MOB1 will transmit the Individual Distress Relay call to your vessel. This call will be repeated every five minutes (plus/minus 6 seconds). The manual selection of a Distress Alert will not be allowed and will be disabled.
    Please note that the MOB1 has not yet received FCC approval and may not be offered for sale in the USA.”
    David also explained to me that “In practice, because we immediately repeat the first {individual} call when GPS lock is gained, you will actually get two calls initially in a close space of time, the five minute interval from the second call. For units where it is allowed, then a five second button press will send one single Distress Alert attempt. The button can be pressed again at any time.”
    What I’m learning is that there is no international standard about how a MOB device should do automated DSC calling, but in the U.S. the RTCM has suggested two alternative methods. One is what the U.S. version of the Ocean Signal MOB1 will do while the other is more like what the Weatherdock Pro unit does. But the latter requires a DSC receiver and therefore must be larger.

  5. Jim Hebert Jim Hebert says:

    Regarding how typical recreational chart plotters might respond to an AIS Message from an AIS SART:
    It would be interesting to test the response by having a valid AIS message sequence from a typical AIS SART, and then sending that sequence to a chart plotter over an NMEA-0183 interface by pasting the message into a terminal window on an attached terminal. In this way a number of people could test their chart plotters. All that is needed is a sample of an AIS SART message. If anyone has such a sample message, perhaps they could post it here. I would be glad to test my chart plotters and report the results.

  6. Henning says:

    Jim, I don’t have a valid AIS SART message for you and cannot record one as I don’t own an AIS SART myself at this time. As we all know, the structure of such a NMEA0183 sentence is defined in the NMEA0183 standard, which, if you had purchased it, you weren’t allowed to disclose publicly. But anyone NOT having purchased the standard could record one legally and publish the data here. Those most readily in possession of a sample sentence will be the manufacturers but they will likely all be bound by the standard and cannot disclose.
    But your idea is good and not hard to do. You will need a software tool to create and connect virtual serial ports, though, such as this one: http://www.eterlogic.com/Products.VSPE.html
    I did this when I wanted to test compatibility of Coastal Explorer with the DSC+DSE sentences for incoming DSC calls. I had located a sample sentence on the internet and tested in the way you describe. At first I couldn’t see the result but then, after zooming all the way out, I found the red dot very close to 0 degrees latitude/0 degrees longitude, to the west of Africa. The friendly poster of the sample sentence must have gotten the decimal places wrong 😉
    But note this tests for compatibility with NMEA0183 only. For NMEA2000 you would probably want to look at Kees’ Canboat software, to be used with an NGT-1, and learn how to build a binary NMEA2000 PGN. Or else use a NGW-1 with the terminal window-method (but this may introduce errors due to the conversion).
    Also, many or all AIS SARTs will support a test mode and there is a test sentence defined in the standard along with a test “AIS SART Active” symbol to be displayed on the chart. Very helpful to test range, for example, but I would still look for a way to test the real message. My feeling is that all developers and product testers will always or nearly always use the test message and so the real message may never have been used, ever. Didn’t Garmin have a problem once where the entire MFD froze on receipt of the real message?

  7. Jim Hebert Jim Hebert says:

    Henning has made an interesting observation. Let me expand it a bit.
    The contents of the AIS messages that are to be sent by the RADIO transmission are well defined and documented in open standards. It seems that the NMEA data sent from an AIS receiver as a result of receiving these radio transmission has somehow become considered a secret or at least something that NMEA is unwilling to disclose without payment and binding the recipient to further secrecy.
    It is quite simple to feed the NMEA-0183 serial data output from an AIS receiver into a terminal and capture the data. I have done this often as a way to compare the response of chart plotters to the same input data. If I only had an AIS SART available for a few short hours, I could record the output of my AIS receiver when the AIS SART was sending a TEST message.
    ASIDE: A very capable computer navigation program, PolarView NS, will write incoming NMEA-0183 data from an attached AIS receiver into a log file. The software is also so versatile that it can then play out the data from the log file and send it as NMEA-0183 output on the terminal’s serial port. I use this method to first record AIS data, and then to play it out to various connected chart plotters to see what they do with it.

  8. Ben Ellison Ben Ellison says:

    Hi Jim,
    I think you’ll find this site useful:
    http://catb.org/gpsd/AIVDM.html
    You can also get a sense of what AIS SART test messages look like in NMEA 2000 format from the screenshots here:
    https://staging.panbo.com/archives/2011/05/ais_sart_plotting_nmea_2000_ais_problems.html
    I have logged AIS SART tests but would be hardpressed to find them, and the test gear is 1,000 miles away right now. Sorry.
    Note that logging AIS NMEA 0183 output is fairly easy. Every transponder setup utility program I’ve seen can do it, and some transponders can record the 0183 stream right to an SD card.

  9. Jim Hebert Jim Hebert says:

    Yes, I am familiar with that site. I could try to roll-my-own NMEA message from an AIS SART. But I wouldn’t be certain my message would be the same as the actual message from an AIS SART.
    If crafting your own NMEA messages you will find it necessary to generate a valid checksum, and for that I found it very useful to let a checksum calculator do the work, like this site’s:
    http://nmeachecksum.eqth.net/

  10. Dan Corcoran (b393capt) says:

    Well done Henning! I enjoyed reading this.

  11. Jim Hebert Jim Hebert says:

    I have obtained a sample AIS-SART message and simulated reception of it and connection to my chart plotter. I show the results in a separate article
    http://continuouswave.com/ubb/Forum6/HTML/003687.html
    as there are several screen captures involved which can’t be easily incorporated here.
    Thanks to Weatherdock AG for supplying the sample AIS-SART message.
    The executive summary: the chart plotter responded to the AIS-SART as if it were a normal position message from a Class-A vessel; no alert or alarm was raised.

  12. Ben Ellison Ben Ellison says:

    Thanks, Jim, but I’m surprised at your HDS results. In this 2011 entry you can see a Lowrance HDS12 putting up a SART ACTIVE alarm in response to a Weatherdock easyRescue:
    https://staging.panbo.com/archives/2011/05/easyrescue_personal_ais_sart_hands-on_1.html
    It’s not uncommon, though, for older MFDs to only see an AIS SART’s Class A position message, which is one reason the Ocean Signal’s DSC alarm seems like a good idea.
    But then again a lot of current MFDs handle AIS SARTS and their AIS MOB sisters well, as shown here:
    https://staging.panbo.com/archives/2012/09/ais_mob_sart_display_garmin_nails_it.html
    Today’s entry about the Vestas shipwreck also shows Expedition charting software handling a Kannad AIS MoB SART nicely.

  13. Jim says:

    Ben–The screen shot in your prior article looks like a SIMRAD device, not a Lowrance HDS. My HDS-8 is up-to-date on firmware, but it is the older generation. Also, perhaps the range to the target, in my case 4,000-miles, suppressed an alarm. Unfortunately, that was the only test sentence I had to try.
    Since there is at least one generation (and perhaps soon to be two generations) newer Lowrance HDS devices now in production, the response to AIS-SART signals of the newer devices may improve compared to my c.2010 device.
    I did notice the AIS-SART reporting on the chart plotter screen seen in the article on the VESTAS grounding. That was quite a coincidence in terms of this discussion.

  14. Ben Ellison Ben Ellison says:

    You’re right, Jim, the screen shot is from a Simrad NSE but as I wrote in the entry “…the Lowrance HDS and Simrad NSE also threw up a useful message alarm as you can see on the screen below.” I can recollect the scene in my basement lab now and it was actually a first generation HDS10 I’d been loaned in 2009 and obviously the test was pretty close to real world. It was this guy:
    https://staging.panbo.com/archives/2009/08/18_radome_testing_part_2.html

  15. The only way to ring an alarm from a MoB is by using DSC…

  16. Ben Ellison Ben Ellison says:

    Thanks, Glenn, but I’ve seen MFDs that do recognize an AIS MOB signal like a regular MOB button alarm and can extend their weak alarm “beep” to a loud external alarm. I’ve even heard of offshore racing boats that install a small Garmin MFD specifically to handle MOB AIS alarms.
    https://staging.panbo.com/archives/2012/09/ais_mob_sart_display_garmin_nails_it.html
    But I too really like AIS MOB beacons with the added DSC feature — like Ocean Signal’s — because just about every boat out there is already set up for very loud DSC alarms.

  17. Kevern says:

    Seems OpenCPN is compatible with the AIS MOB messages.
    http://opencpn.org/ocpn/AIS_SART

Join the conversation

Your email address will not be published.