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Updating IMU after firmware update

Discussion in 'General Discussion' started by Steve Spain, Jul 10, 2016.

  1. Steve Spain

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    After updating firmware, is it always best to update the IMU? What is the purpose of the IMU check, if it says the IMU is good, yet one still needs to update the IMU?

    And thank goodness for this forum. Updated 10 days ago and flew a little to test, then just caught wind last night of the firmware issues on this forum. Just did the newest (07/07/2016 xxx.30) upgrade and will fly a lot this week testing before a big job next week. I didn't get any alert from DJI about an update to the update!!

    Thanks!

    Steve
     
  2. The Editor

    The Editor Moderator
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    Although not referenced anywhere in the manual it is always good practice to calibrate the IMU after a firmware update since we have no idea what DJI has written into their code with respect to algorithms and baseline calibrations for specific hardware modules.
    By calibrating after a firmware update you are effectively giving the new code a baseline null reading on the sensors which cannot be a bad thing.
    By checking the IMU mod values before each take off you are ensuring there is no anomaly readings being fed back to the flight controller from any of the Mems Gyro units/accelerometers etc which at rest should be stable.
     
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  3. Steve Spain

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    Thanks for your advice, and will continue to do that as a best practice.

    Flew my Inspire1 Pro with the latest firmware (xxx.30) without any issues today, for what it is worth.

    As someone who writes software, I wonder why DJI doesn't have code that requires IMU, compass and stick calibration before giving the green "Good to Fly" after an update. It would be easy to do.
     
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  4. LLWS

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    They probably omit an IMU recalibration because the software coders can't assure the Inspire will be on a level surface during the update.
     
  5. Steve Spain

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    Yes, but they could easily prevent flight until the IMU was updated ( just like these new pop ups that you have to agree to before proceeding for flight that warn you about restricted airspace.)
     
  6. Dave Armbrust

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    If you were to ask them they would probably say "because it is not necessary". This is probably true 99% of the time as they probably do not normally update the drivers that calibrate the IMU.

    It is just good "best practices" to recalibrate anything that can be recalibrated everytime you do a firmware update for two reason.

    1) It can not hurt
    2) Just in case they updated the calibration drivers and failed to mention it.

    Can you just do an IMU check? Probably, but I still believe it is best to do a recalibration for the same two reasons.
     
  7. lake_flyer

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    I recall (to recall) that DJI used to have more info on IMU calibration during the past years. But that must have been in a parallel universe. I have been searching the DJI site but found not one IMU calibration advice for the Inspire1, except in the maintenance manual.
    On the other hand, they keep telling to calibrate the compass before every flight.

    A serious glitch while updating the FW could however knock off the IMU settings in ways you couldn't imagine, which I experienced one time with one of my Phantoms. You don't speak of bath tubbing anymore. It becomes almost uncontrollable. For a lots of people this would seem like a fly away, ' the bird had a mind of its own'.
    So if it's ever wise to do a IMU cal, it's after a firmware update.
     
  8. Vincenzo

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    I have owned the Inspire 1 for more than one year now and it has hundred of flights. I have never calibrated the IMU, neither after firmware upgrade nor after the multiple courier shipments from Ireland to Italy and back.

    Surely isn't necessary, but may be worth checking the calibrations just o case they are off even before FW update...

    V.