MAVIC PRO Start Up Time

Discussion in 'Mavic Pro Discussions' started by CAPTAINDRONE, Nov 19, 2016.

  1. CAPTAINDRONE

    CAPTAINDRONE Well-Known Member

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    When I first received the Mavic Pro a few weeks ago, I took it out to my local field, did the compass calibration and the Mavic was ready to fly in about 30 seconds (upper screen turned green - Ready to Fly). The weather was mild, perhaps 14 C (57 F).

    I've done one firmware update since that time (whatever the latest firmware is).

    Lately, as the weather gets colder, the Mavic takes a long time to get into Ready to Fly state. The Red "Can't Fly" & No GPS seem to stay on the screen from 1 to 3 minutes or longer before it's ready to go. Subsequent startups (with a battery change) are much quicker.

    Is anyone else having lengthy start up times?
     
  2. jamgabbi

    jamgabbi Well-Known Member

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    same IMU warmup is longer not sure if its weather related or not its been in the 50s in NYC
     
  3. barefootFPV

    barefootFPV Member

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    A friend of mine who's a long time DJI pilot recommended doing my IMU calibration after keeping my Mavic in the refrigerator for 10 minutes.

    Apparently, the trick is pretty common amongst phantom owners.

    Sent from my Nexus 6P using MavicPilots mobile app
     
  4. sdharris

    sdharris Well-Known Member

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    Not the refrigerator, that is a bit too extreme and can introduce moisture. If its cool outside leave it outside for 10 minutes or some people put it in front their AC. Then the trick was to have your RC and DJI GO ready and get into the IMU calibration as quickly as possible on power on.

    I have to say though I have performed two firmware updates on mine and travelled from the UK to the US and back again and have not performed an IMU calibration yet, but I have performed one compass calibration. Mine is ready within seconds and flies fine.
     
  5. TheLightSpeed!

    TheLightSpeed! Well-Known Member

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    You're not supposed to do a CALIBRATION of the IMU. However many are.

    From the factory the Mavic says to leave it alone. Unless the app says to do it.

    However if you do getting it cold in the fridge is fine


    Sent from my iPhone using MavicPilots
     
  6. msinger

    msinger Well-Known Member
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    It's perfectly safe to calibrate the IMU at anytime as long as it's done properly like this.
     
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  7. TheLightSpeed!

    TheLightSpeed! Well-Known Member

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    @msinger - you and I keep going round and round about this.

    Show me in the manual where it's recommended when you get you Mavic and before your first flight and I'll shut up!

    Otherwise, I wouldn't recommend doing it unless it prompts you too!



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  8. msinger

    msinger Well-Known Member
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    The manual does not mention this. It also does not warn people not to calibrate it unless prompted by DJI GO.
     
  9. The Editor

    The Editor Well-Known Member

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    I believe the problem (difference of opinion) stems from individuals like @msinger and my self (and others) who have years of multirotor and RC experience having designed, bulit and flown airframes from scratch and understanding in depth exactly what a flight controller is doing, how it works and precisely what a mems gyro and accelerometer (IMU) unit needs to do to maintain aircraft attitude.
    We come from the old school of understanding why, what, how and the cause and effect of not doing something wheras a lot of new 'out of the box' flyers are blindly following the adage that 'it it doesn't say it in black and white in the manual it must be bad advice'
    Not trying to be clever - just a difference of opinion. However what I would say is don't write off advice from a combined experience of hundreds (probably thousands) of flight hours and competence on multiple platforms just because 'The manual doesn't say so'
     
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  10. CAPTAINDRONE

    CAPTAINDRONE Well-Known Member

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    I've always been amazed with DJI's "heating up requirements" before flight. I'm sure it's a beneficial thing which hepls to ensure everything is zero balanced before flight, but it becomes a bit annoying.

    I've owned (to date) 6 DJI drones (Phantoms & Mavic). I've flown at all times of year in different weather. Sometimes the Phantoms were ready to fly almost immediately and other times the "Warming Up" would be displayed or "Ready to fly in Non GPS mode" until GPS was acquired. The Mavic just says "Can't Fly". In the end the start up times are never consistent especially in colder weather.

    I also fly a Typhoon H. Yuneec has long fixed the start up time on this drone. It takes just over a minute to acquire sufficient sats on the controller and drone before it is ready to fly in warm and cold weather (always the same). This tells me that the DJI products have some internal component that is affected by the environment which must be at a certain pre-configuration prior to launch.
     
  11. CAPTAINDRONE

    CAPTAINDRONE Well-Known Member

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    I see what you're getting at but since the owner of a drone can't hold anyone responsible for what they do or do not do, other then themselves, they are less apt to follow experienced advice if it doesn't place their mind at ease.

    Since drone technolgy today is far different from a year ago it then becomes a continued learning experience for even the experienced.... Which is another reason these forums are so beneficial.
     
  12. TheLightSpeed!

    TheLightSpeed! Well-Known Member

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    You also come from a school of lesser technology. While you build from scratch, you didn't build software I presume, nor were any of us on the design team for this product.

    The DJI team clearly didn't feel it necessary to have everyone calibrate their IMU's... who are any of us to make up our own rules and speak for DJI to their customers and recommend something they themselves didn't feel inclined to include.


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  13. msinger

    msinger Well-Known Member
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    Some members of DJI support are aware of best practices that don't appear in DJI manuals. See this post and the post that follows it.
     
  14. The Editor

    The Editor Well-Known Member

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    I also come from being a DJI beta tester and have good relationships with both DJI R&D and Edward Windham at DJI - this is all well documented over on Inspire Pilots where I am a Moderator. With over 6,600 posts and nearly 4,000 'likes' I have clearly managed to advice and help just a few people with issues and problems with their DJI machines
    Notable Members | DJI Inspire Forum
    Although I am NDA'd with DJI so am somewhat shackled in what I can and can't say you will also see that I knew far more about the release of the Inspire2 than most people, either in the press or on any PooTube site.
    I was one of the first individuals to advise against calibrating their compass before every flight or even when moving location (again this is well documented over on Inspirepilots and goes back over two years ago).
    I explained the reasoning and theory behind it and eventually DJI agreed with my method and reasoning and indeed they actually now advocate not calibrating all the time now - a 180 degree change from their previous advice.
    I also hold a degree in electronics engineering and have commercial certification from the CAA for SUAS operations.
    Do I understand these machines? - Yes I do.
    So I feel it a little presumptuous of you to say I come from lesser technology, however, if you prefer to find your answers in the manuals of DJI that is of course your prerogative. Sometimes however, real world experience has and can provide the answers where a manual is lacking.
    I will try and help people wherever I can, whether they wish to listen is of course their desicision :)
     
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  15. DrPeppar

    DrPeppar Well-Known Member

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    I have the issue too. When I first got it it booted right up and in the air in seconds.
    Now every time its warming the IMU.
    A calibration may be in order.
    My thinking for all the IMU issues are having a flat take off surface. With the design as it is, I have fewer options readily available unless I want to cut grass.
    Most of my take offs are from less than perfectly flat surfaces now so I believe that explains IMU problems at least for me.
    What do you think? Plausible?


    Sent from my iPhone using MavicPilots
     
  16. flyNfrank

    flyNfrank Active Member

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    I like what you're sayin' but when it's all said & done, the blame for what you're saying has to be placed on those same people of seniority. We constantly say things directed to manual. Such as..."what did the manual say?"..."did you read the manual 1st, before hand?"...."the manual is your best friend"...and so on.
     
  17. CAPTAINDRONE

    CAPTAINDRONE Well-Known Member

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    UPDATE. Tried starting up the Mavic Pro in my house beside a window so that it could acquire GPS. It started up super fast. I guess the issue is the outdoor environment which is causing the slow start ups.
     
  18. Brutus

    Brutus Member

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    On the DJI forum I saw a post where was stated that the temperature during IMU calibration is the new "warm up" temperature. Therefore it's advised to keep the aircraft as cool as possible before starting calibration. It was advised to lay it in a AC room before calibration. If you calibrated at livingroomtemperature, then that temperature will be your new "warm up" temperature. Therefore the start up time will look shorter.
     
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  19. kmaluo

    kmaluo Well-Known Member

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    Curious, why is the IMU temperature driven, and if you can just calibrate it at a different temperature to trick it to boot faster, then what's the point? Thank you.
     
  20. Kilrah

    Kilrah Well-Known Member

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    Sensor drift varies with temperature.

    This gets mapped during the calibration, given the IMU will heat up during the rather long calibration process the FC can learn how the sensors behave over a significant temperature range, and it then wants to be in that range for flying. If the IMU is initially colder the FC will wait until it gets back in the known range through the heat generated by the electronics around before it lets you go.
     
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