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Thread: How do I reflect RPi time synchronized with PPS of GPS to fr24feed?

  1. #1
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    How do I reflect RPi time synchronized with PPS of GPS to fr24feed?

    Hi all,
    I'm feeder of using RPi with current version fr24feed software.
    My RPi is equipped GPS receiver and system clock is sync to GPS using PPS via GPIO. Therefore, my RPi's system time deviation from GPS time is less than few nano-seconds from GPS standard time.
    I supposed it should be helpful for FR24 MLAT system to determine the a/c position computation more accuracy.
    However, when I configured /etc/fr24feed.ini as 'mlat-without-gps="no"', then fr24feed began to look for GPS connection and it doesn't start working.
    Does anyone know the way to let fr24eed software know that this RPi has time of date from GPS?

  2. #2
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    You can't. All sources need the same time souce so the system currently used NTP only.

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  3. #3
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    Hi Oblivian, thank you very much for your quick reply. I understood.

    However, I disappointed to fr24 team about choice of their time source.
    Fr24feed is referencing pool.ntp.org NTP server. It is an unstable time source for synchronize between multi computer.

    As you mentioned, accuracy of contributed MLAT is based on synchronization of all time source for all feeders. But pool.ntp.org is not..


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  4. #4
    Purser
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    Not an expert on RPis, but on standard linux you can configure the local NTP daemon to use a GPS receiver to set the system time. Is that not possible on RPis?

  5. #5
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    If you keep an eye on the console, you'll see this..

    I'ts built in to the app so ignores external processes.

    ntp.jpg

    (yes, my laptop has a fast clock for some reason)
    Posts not to be taken as official support representation - Just a helpful uploader who tinkers

  6. #6
    Administrator piopawlu's Avatar
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    System time is never used for MLAT calculations. It's only for reference when ADS-B data arrives in our servers and therefore nanoseconds differences are negligible.

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