GPS Time Issue (somewhat like Y2K)

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  • #10152
    Tom Easterbrook
    Tom Easterbrook
    Participant

    I just came across this posting on another forum today. I had not even heard about it before this! I just talked on the phone to Raymarine support, as my equipment is late 1990’s early 2000 vintage (the boat is a 2002 model). The tech stated they were “testing and did not yet know the total impact and that they would be posting information on their website soon”. I don’t know about you, but isn’t that a little bit late, especially since this isn’t the first time (1999 was and not the Y2K thing but the GPS issue) this “rollover” has happened.

    If you have older (older than just a few years old) MFD and GPS you might want to look into this with the manufacturer.
    The post I found:
    “Older satnavs and such devices won’t be able to use America’s Global Positioning System properly after April 6 unless they’ve been suitably updated or designed to handle a looming epoch rollover. GPS signals from satellites include a timestamp, needed in part to calculate one’s location, that stores the week number using ten binary bits. That means the week number can have 210 or 1,024 integer values, counting from zero to 1,023 in this case. Every 1,024 weeks, or roughly every 20 years, the counter rolls over from 1,023 to zero. The first Saturday in April will mark the end of the 1,024th week, after which the counter will spill over from 1,023 to zero. The last time the week number overflowed like this was in 1999, nearly two decades on from the first epoch in January 1980. You can see where this is going. If devices in use today are not designed or patched to handle this latest rollover, they will revert to an earlier year after that 1,024th week in April, causing attempts to calculate position to potentially fail. System and navigation data could even be corrupted, we’re warned.”

    https://ics-cert.us-cert.gov/sites/d…n_GPS_2019.pdf

    Just an FYI in case, like me, you had not heard about this.

    Don’t panic, just be aware and at least checkout the manufacturer’s website for info.

    Regards,

    Tom Easterbrook

    Pilitak NT 37-068

    #10426
    Tom Easterbrook
    Tom Easterbrook
    Participant

    Well,

    Today is the day. Apparently it will (or will not) affect different makes and models differently (even some fairly new units). Raymarine has a technical bulletin out dated April 1, 2019 (not an April Fools joke) updating what they are expecting for a large list of their products (including legacy products). My GPS, an RN300 model, is listed as potentially having date issues from 2017. I never noticed, but I do not use that GPS for tides or currents. I fix is available for my unit, just replace the GPS antenna.

    Hope no one here will experience any difficult problems with this,

    Tom

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