SRT acquires Class B AIS patent, consequences uncertain

Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

23 Responses

  1. Ross Norsworthy says:

    It seems to me that you can’t tell everyone the patent is for their protection and does not incur remuneration, and then some day we wake up and find out we owe a boatload of back payments and payments going forward. That is entrapment in anybody’s ethos.

  2. gobsmacked says:

    “SRT and Mr. Johnson have entered into an agreement to exploit the commercial potential of the Patent.”
    ​”​I see no valid reason why the licensing of a long known and established patent which ensures a technology standard works well should affect end user pricing​”
    “We estimate that the average Class B retail price is in the region of $700, thus indicating a per unit royalty of $35 per unit. Our legal right to the per unit royalty extends to all sales over the last 6 years prior to our first expression of rights, and then going forward in the future. Thus, there would be a lump sum in regard to the arrears and then quarterly payments on sales until March 2019 when the patent expires.​”​

  3. Ben Ellison Ben Ellison says:

    Let me add that if you have some professional connection to the AIS industry or related regulatory bodies, please at least state your affiliation. That and other Panbo commenting policies here:
    And no offense meant to Ross Norsworthy — he did use his real name and I’m not even sure he has a stake in AIS anymore — but he certainly had a stellar career in the field:

  4. JoeH says:

    Ben, Ross has been an engineering consultant to the Coast Guard for many years and he’s still in that capacity today. He’s a member of IEC TC80 and their WG15 on AIS as well as the IALA eNav committee’s working group on AIS. He’s still active in AIS and in particular development of its high speed terrestrial/satellite expansion VDES (VHF Data Exchange System).
    He’s also chairman of RTCM’s SC 131 committee developing a standard for a multi-system shipborne navigation receiver, and is on the RTCM board.

  5. maestro says:

    As an ex-employee of SRT, I can’t help feeling that Mr Tucker is desperately trying to find some additional income to counter this years poor financial results, especially given the predictions of major profits this time last year.
    Otherwise, I have to echo Ross’s comments. It’s one thing to embark on a development plan for a piece of kit knowing that there will be some IPR payment involved, so it can be factored into the costing, it’s quite another to be un-expectantly hit with it 6 years down the line.

  6. Butch Davis says:

    This reads as though someone has misplaced their ethics or perhaps I’m just too old to understand modern business methods.

  7. Ben Ellison Ben Ellison says:

    I just got this email from David Pietraszewski, who is credited with a major part in CSTDMA Class B AIS development by Joe Hersey above (and who I queried earlier this week):
    “I have been a government retiree for several years; but I continue to work part-time on AIS related work at the USCG R&D Center as a Sonalysts, Inc. employee.
    I did read your article, “SRT acquires Class B AIS patent…”, and found it interesting. You did your research. I agree with Joe’s comments and have little to add. I have no comment on the status or ownership of the CSTDMA patent. But, I know a lot of work went into getting the CSTDMA radio signal correctly defined and tested.
    In the time period (2002-2003’ish) prior to the patent, both IALA and IEC were investigating the possibility that AIS could be expanded to serve more than the IMO SOLAS class vessels, in particular, the recreational boating community. The notion of using an “energy threshold” to detect unused AIS time slots for the recreational equipment’s broadcasts was developed during that period. The CSTDMA concept evolved and matured during those discussions and became a new form of AIS (the ITU AIS standard was amended). As I recall, some of the high-level “Class B” objectives were to:
    – Avoid potential SOTDMA patient issues. At the time, SOTDMA was “free” for IMO defined “SOLAS” vessels only.
    – Seamlessly mesh broadcast content and VDL use with the operation and display systems of the existing Class A units
    – Use the VDL politely with essentially no impact on Class A performance. For example, Class B Carrier Sense units do not cause Class A units to avoid additional “reserved slots.”
    – Provide minimal notice of a vessel’s presence; position, not tracking, being the objective. The update rate was sacrificed to reduce VDL loading, power needs, and component cost. If tracking is essential, a Class A unit should be used.
    As Joe mentioned, I was quite involved in developing the Class B CSTDMA standard; but credit for designing and building working equipment has to go to the industry folks on that IEC working group.”

  8. Ben Cosier says:

    Regardless of the patent outcome, AIS is a crucial safety tool, worldwide. Underpinning it is an “open standard,” even if developed commercially. This “open standard” needs to meet the needs of its users and be commercially achievable (ie financially as well as otherwise) for the many AIS manufacturers. This is crucial to the viability, deployement, stability, upgrades, and overall operation of a key worldwide safety technology, that is AIS.
    I just hope SRT keeps the standard “open” for the benefit and safety of the international marine community. Imagine if VHF marine radio went digital and different manufacturers used different digital standards, or added their own extra features that would only partly talk to other radios (or not at all).

  9. Derek Love says:

    From my recollections, Davids contribution to Class B-CS was instrumental – I well remember his overriding mantra at the IEC meetings – “Do not harm the VDL”

  10. Karl says:

    Ben’s article and the user comments leave me totally confused. If use of the patent was to be “free of charge and non-discriminatory”, why patent it in the first place?
    Why not make it open-source and thus prior art to prevent someone else from profiting from it?
    2003??? The industry moves at glacial speed…look at how long NMEA 2000 (ostensibly named for its year of adoption) took to gain public acceptance, along with a patchwork of proprietary connectors by manufacturer.
    And, rather than going the patent route, NMEA chose the copyright method of closely guarding its secrets. In my opinion, NMEA has done a disservice in not making their bus totally open-source with complete software development kits available to all, not just royalty payers. After all, it is primarily a “fork” of prior art used in CANBUS systems in wide use in other industries, including CAD/CAM manufacturing, for example, probably why it was not patentable.
    I’m obviously missing the entire point of all this.

  11. Ben Ellison Ben Ellison says:

    I agree that you’re missing a lot, Karl, like this sentence:
    “One anonymous explanation of this apparent inconsistency is that the patent was filed only as a potential defense if some other entity claimed CSTDMA rights.”
    That idea is fairly consistent with Joe Hersey’s memory that the patent would be free of charge and non-discriminatory. The patent’s intention may have been only to establish prior art if it didn’t already exist (which is now being reviewed).
    But all this took place 12 years ago, so memories may vary a lot. I sure don’t feel like I know exactly why the patent was filed, though due to Joe Hersey’s and other input I doubt that Mark Johnson filed it with royalty expectations. Hopefully more people who were involved will speak out and the whole story will become clear eventually.
    I’m not going to let these comments sidetrack to NMEA 2000, but note that no manufacturers pay royalties to use N2K. Nor is it a fork of CANbus; it’s an implementation layer built on top of CANbus:

  12. Ben Ellison Ben Ellison says:

    Slightly related news: Garmin is claiming victory regarding Navico’s patent suit over DownVü sonar:
    Marine electronics companies don’t talk about this area much, but there may also be patent issues around side viewing sonar, auto routing, and other technologies.

  13. Martin says:

    Ben,maybe you should also tell the story from the beginning starting with the job of trying to get the whole world adapt a new way of seeing airplanes/ships. That is not cheap, fast or simple.
    This patent discussion feels strange since the whole thing with CSTDMA was avoiding Håkan Lans patent claims on SOTDMA. And now?

  14. Ben Ellison Ben Ellison says:

    More Garmin patent news:
    I’m impressed that Garmin announced this somewhat negative news themselves, but the Johnson Outdoors (Humminbird) PDF further suggests that Garmin may have to stop SideVue sales, at least for a while:

  15. Ben Ellison Ben Ellison says:

    The SRT AIS patent reexamination is not final, but the examiner has tentatively rejected all 14 claims. The 15 page document includes prior art detail for each rejection. To download the doc go to
    fill out the captcha
    search for Application Number “90/013498”
    look for 9/11 “Reexam – Non-Final Action” doc under Image File Wrapper tab
    I believe that SRT now has 2 months to argue its case for patent validity.

  16. Ben Ellison Ben Ellison says:

    Garmin may regret their “Victorious over Navico…” press release now that the ITC seems to have reversed course:
    The issue of side scan patents with Humminbird has not gone well either:
    As for the AIS patent dispute, SRT has filed arguments in support of their claims, as well as new claims, and now the examiner has a while to make a final decision.

  17. Ben Ellison Ben Ellison says:

    Garmin plans to appeal ITC ruling and says it “will have no impact on Garmin products already purchased by our customers and dealers, or any products purchased going forward.”
    Which is quite a difference of opinion from Navico’s take on the situation.

  18. Ben Ellison Ben Ellison says:

    Garmin put out a dealer service bulletin that’s even more emphatic about Navico’s press release being “inaccurate and misleading”…

  19. Ben Ellison Ben Ellison says:

    $37,000,000 serious is where the Garmin/Navico downscan patent dispute has gotten:
    Garmin claims that ClearVu products are not affected by the dispute, but Navico claims otherwise, and made a video to illustrate:
    Meanwhile, Garmin sued Navico, and Raymarine/FLIR, over their marine auto guidance (auto routing) in the U.S.:

  20. Ben Ellison Ben Ellison says:

    Reversal! Garmin is claiming quite a victory:
    But maybe Navico will weigh in?
    This subject is also being discussed on the Forum, which is probably a better spot for it:

  21. Ben Ellison Ben Ellison says:

    I think the Class B AIS patent is dead. The paperwork has piled up and just maybe another appeal is possible, but on 8/24/17 three judges on the U.S. Patent Trial and Appeals Board affirmed the Examiner’s prior rejection of claims.
    Meanwhile there’s another turn in the Garmin/Navico battle, this time affirming the huge fine against Garmin apparently despite their patent victory:

  22. Ben Ellison Ben Ellison says:

    Nice! Apparently Navico and Garmin made peace regarding sonar patents. Both companies sent the exact same press release this morning:

  23. Ben Ellison Ben Ellison says:

    The Class B/CS AIS patent is still alive, as you can see by searching…

    …for application “90/013498” and dive into the Image Files. But — as I understand the documents — the patent claims have so far been rejected by an examiner and then by an appeals board, and are only being reexamined because the board rejections were based on different reasons than the examiner.

    Also, almost all the original claims have been canceled by SRT and Mark Johnson, and many new claims were added. While that’s allowed, I’m told that if the patent survives this process, it will likely not apply to Class B transponders already built.

    Meanwhile, Class B/SO is coming on strong and getting rapidly less expensive, and this patent has nothing to do with it. If you check the FCC for AIS, you’ll see numerous new ones already approved:

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