Vakaros Atlas 2 RaceSense & the promise of dual-band GPS

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.

10 Responses

  1. clay babcock says:

    Ben,
    Thanks as always for your insightful dives in to complex marine technology! We at Vakaros are very proud of the Atlas 2 and RaceSense, but realize there is a lot to take in. Your post adds not only a solid bit of clarity to that, but also a 3rd party perspective as well. Thanks again.

  2. Hi Ben! Glad to hear you’re staying un-frozen up there! The software looks interesting for racers (not me, but I love to watch!) and dual-channel GPS (it seems to me that “dual band” would imply a wider frequency split than what they’re doing) certainly has potential for very high levels of precision – and error checking. Both things you’d like to have going for you on a dark night and an unfamiliar entrance πŸ™‚
    What I have significant doubts about is getting usable range from a Bluetooth device in a race-boat environment. I went over to the calculator you linked to, but even at +20 dBm (100 mw) transmitting power, getting the stated 1 km range requires antenna gains that I think would be unrealizable for an omnidirectional antenna in a boat that heels and pitches. And having the boat that is doing a horizon job on the fleet drop out of the network will cause some hard feelings, I predict! Perhaps they are considering reducing the bandwidth to achieve greater receiver sensitivity, which would help, but introduces some other potential issues as well.
    IMHO, this scheme needs a more robust communications layer – something like the digital comms that some manufacturers were looking at with dual-use of marine channels, maybe? It seems to me that high speeds aren’t required, just solid reporting of position and a few other variables. While allowing cellular linking would help out, do most sail-race areas enjoy good cellular coverage? Our experience sailing around suggests otherwise πŸ™‚

  3. Clay Babcock says:

    Harley,
    Thanks for the comment and you are right, the application, comms, and PHY layers all have to be tuned and optimized to make this work. A lot of that we do, some it it we get for free with BLE 5.0. So far, we’ve been happy with our test results.

  4. Clay Babcock says:

    For what its worth, the space agencies (USAF, ESA, etc) call them bands, so we go with that.

    best,
    Clay

  5. I did an internet search to see what “multi band GNSS” really meant – and I see that the term “band” is being used in the same sense that the cell companies are using it, rather than the traditional sense. So I stand corrected – within the industry, L1, L2 and L5 are considered separate “bands”, even though they are fairly closely adjacent frequency-wise. In any case, I agree that this is a good thing πŸ™‚
    As far as robustness in a race-boat environment, I suggest you seek out a suitable yacht club and equip their fleet of club racers with a test system & see how it works – if they can’t break it, it’s probably good to go!

    Hartley
    S/V Atsa

    • Clay Babcock says:

      While we’ve been working on RaceSense for several years, the timing of the announcement was to allow us to start working more openly with partners. In that regard, we’re putting plans in place with some of the biggest OD fleets, and several of the world’s most prestigious Yacht Clubs to start trails. It’s going to be a fun spring!

      • Sounds like it! Me, I’m just hoping for a mild winter and for Victron to deliver our new house battery πŸ˜‰

        I did some reading about BLE – I note that the throughput is well below what traditional Bluetooth offers, but significant extra range (presumably because of reduced bandwidth allowing higher receive sensitivity?) – though the stated maximum range is 150M in open areas, I’m sure it can be made higher.
        I’m sure those YCs will give you a lot to work with!

        Hartley

  6. Ben Ellison Ben Ellison says:

    Hiya Hartley, There seem to be many BLE configurations and the Bluetooth SIG link I put in the entry claims that over 1 km range is possible:

    https://www.bluetooth.com/learn-about-bluetooth/key-attributes/range/

    More about long-range modes, aka “Coded PHY”:

    https://www.novelbits.io/long-range-bluetooth-coded-phy/

    • Hi Ben! Yes, its clear that the 125 kB mode gains significant performance, presumably by reducing bandwidth and enhancing error-correction. But its still straining at maximum TX power (100mw) to get to 1 km. I also note some odd inconsistencies in these pages – in the novelbits.io page notes that the “LE S=8” mode achieves -82 dBm receive sensitivity, while the calculator assigns -101 dBm to “LE 125K” – quite a difference for what I think is the same mode!. There may well be some underlying differences that are not visible, but I don’t know what they would be.
      In a racing sailboat environment, I don’t think its going to be possible to achieve 2 GHz antenna gains greater than perhaps 6 dBi without going to aiming or leveling mechanisms.
      My feeling is that they will discover its necessary to place additional MESH-net members across the course to ensure coverage. A more robust transport layer would be ideal – but the constraints of licensing, etc. make this a touchy subject at best, especially for an international product.

      Hartley

  7. Brole says:

    Hello to everyone!
    I am about to buy Vakaros Atlas 2 with Calypso windmeter. Is there more than one version (generation) of Atlas 2 product? I dont want to buy something old without some new features. Another question. Does Calypso windmeter wirks well and provide all features of Atlas 2?

    Thanks for answering.

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