Will the GPS-Week Rollover kill your GPS?

Discussion in 'GPS Software' started by Pieter du Preez, Apr 9, 2016.

  1. Pieter du Preez

    Pieter du Preez

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    Will the GPS-Week Rollover kill your GPS?

    After reading:
    - Trimble Geoexplorer 1,2 date problems
    https://www.gps-forums.com/threads/trimble-geoexplorer-1-2-date-problems.40149/
    and
    - Trimble Geoexplorer Date Problem
    https://www.gps-forums.com/threads/trimble-geoexplorer-date-problem.37427/


    On the 13th of Feb 2016, overnight I lost 15 of my Geo-Explorer 3 GPS's

    This is due to a small (one line) date entry in its firmware that the suppliers do not want to fix, why - because they can make 2 years' salary of me if they can force me to buy 15 new Nomad GPS's, a touch screen unit that I don't want!

    If something goes wrong with Toyota's accelerator they fix it
    If something goes wrong with Boeing they fix it.
    If something goes wrong with Microsoft... ok, they patch it :)
    And atleast they let you know that you will run into trouble

    I'm wondering when the GEO-XM, the 5700 and the 5800 receivers will run into trouble?
    Can they not atleast warn us in advance?

    If I had the code I could fix it myself but everything is protected and encoded.
    If I could buy new GeoExplorer 3 GPS's at the price of a Nomad, I would probably consider it.

    Currently I have a teenager trying to decode the firmware to see if we can fix it.
    High-hopes, (optimistic), yes, I know, I am willing to pay for a sollution on the Geo-explorer 3 (WITHOUT THE TOUCH SCREEN)

    If you think I am angree, consider the fact that my whole company with all its projects came to a standstill.
    Why did they not warn us? They knew we are still using the old Geo3 GPS's
    Will they warn us that the other units will also stop working?

    I assume there are other users with suppliers / sellers also in this situation, can you please let us hear from you?

    They should sell their product with an expiry date
     
    Pieter du Preez, Apr 9, 2016
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  2. Pieter du Preez

    Nuvi-Nebie Moderator

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    Have you contacted Trimble to see what support they are offering?
     
    Nuvi-Nebie, Apr 9, 2016
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  3. Pieter du Preez

    Pieter du Preez

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    LOL
    yes!
     
    Pieter du Preez, Apr 9, 2016
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  4. Pieter du Preez

    Nuvi-Nebie Moderator

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    Any chance of you telling the other members of the forum what their reply was?
     
    Nuvi-Nebie, Apr 10, 2016
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  5. Pieter du Preez

    Pieter du Preez

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    These responces was via a supplier / agent locally

    The first responce:

    “I've talked to engineering and that's their responce:

    That's an unusual situation! We don't believe there's any time bomb present in the firmware, but it is likely that some aspect of the GPS system has caused the firmware to crash. The reported error indicates a general access violation, which means that some part of the code tried to access data where it should not. This could be due to a calculation that was coded all that time ago not expecting values that it generates today.

    It's hard to know exactly what and, without trying to reproduce this ourselves (which would be hard as all the development systems for that product are gone), we're stuck to provide an answer.”

    The second responce:
    GPS has a ~19.7 year rollover as only a 10-bit week number is used. In our systems to get around this we have a “reference” week number, if we decode time from GPS that is before this week number we know the week number is rolled so we extend the time by adding 1024 weeks. This theoretically always gives us approx. 19.7 years before the firmware will “die” with a week number rollover and so we no longer have issues on integer multiples of 1024 weeks from the GPS reference week 0. In reality we only bump the reference week number about once a year and usually set it to about a year in the past to allow for older simulation scenarios to be used. This results in the firmware having a life span of ~17-18 years
    Consequently I believe some receiver firmware will die this Feb, we know from a customer that tested the DSM132 that firmware dies in Feb 2016 and I suspect many other older (long obsolete) products used the same early version of Firmware with the same reference week number.

    While I have not tested any old products or reviewed their code I would not be surprised if the 4700, 4800, MS750 along with some older Ag receivers have this problem, if they don’t fail in Feb they are likely to fail soon as I think the most recent firmware for those products is now very old (~15+ years old). As firmware has not been built for these products in many cases for over a decade it may be very difficult if not impossible to update the firmware.

    Other reponces:
    - The old 386 PC does not start anymore and there is nobody left in the company that can do the old programming on the old development software (C++?)
    (My thought - even I can still program on GW-Basic and Visual Basic)
    - Beware of the other units ( older than 10 to 15 years?)
    - They would rather I purchase new products to be save


    Responce to questions like when will the other Geo's "die" - they don't know
    How safe is the 5700 units - they don't know
     
    Pieter du Preez, Apr 10, 2016
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