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IMU calibration in the cold
1292 5 2018-1-14
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solentlife
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Flight distance : 1087530 ft
Latvia
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This is something that we get to hear about and I think most like me - tend to ignore it.

We go outside in the cold with our warm batterys and power up ... then wait a minute or so while AC warms up ...

I did ... till few days ago.

With temps dropping and likely colder weather - I went through the IMU calibration outside in -5C ...

I made sure AC was stood long enough to really go cold. I had battery ready but away from the AC.
I started up everything else so all was ready ..

Plugged in battery and immediately to calibration ...

Now - I go outside and I have near instant flight capability ... no waiting.

Nigel
2018-1-14
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DJI Susan
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Hey Nigel, thanks for sharing your experience with us. The warm-up is mainly for the battery, it should be ok as long as it reached the working temperature.
2018-1-16
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solentlife
Captain
Flight distance : 1087530 ft
Latvia
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My batterys are warmed in the bag or pocket.....

Cheers
Nigel
2018-1-16
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Genghis9
Captain
Flight distance : 961 ft
United States
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Would you bother to explain to us why it is helpful to perform the IMU calibration when the bird is cold soaked?
I read about it some months ago but forgot the details and the reference for the info on it.
Did you do this for both drones?
Thanks
2018-1-16
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solentlife
Captain
Flight distance : 1087530 ft
Latvia
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My P3S is donor for my 450 FPV ... so not applicable.

The reasoning is that the IMU references to the temp at calibration ...

If as most do the IMU in summer or warm environment - then the AC itself takes time to warm up, regardless of battery.

I always have warm batterys - use of the warm bag as linked to many times - but until I re-calibrated in cold temp - I always had to wait a minute or so for AC to warm up and give me P-GPS.
Once I calibrated in -5C - the power up and ready to fly is near instant.

There is a fundamental difference for me when calibrating ............ I do IMU outside where I know Compass is good as well.  The last line of numbers in the IMU set are Compass ... so regardless of 'experts' claims - I still note that they similarly cycle through during IMU calibration.
So I make sure I do this outside in safe area.

I know many people do IMU indoors ... but I no longer do and it may be overkill on my part - but I'll stick to that.

Weather here is now averaging -10C ... if it was not so windy - I know I can now go out and literally throw warm battery in and within seconds be in the air ... reducing the time I AM out in the cold ...

Nigel
2018-1-16
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Aardvark
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Flight distance : 384432 ft
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United Kingdom
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solentlife Posted at 2018-1-16 05:38
My P3S is donor for my 450 FPV ... so not applicable.

The reasoning is that the IMU references to the temp at calibration ...

This was the same procedure muted for the P4 IMU calibration (with refrigeration being suggested by some, a bit severe I think), with the same advantage of reduced IMU 'warm up' time.

And it worked.

For the P4 now the procedure has changed, I've done IMU calibration at room temperature and still get sub 5 second IMU warm up time. Previously this might have resulted in a 30-60s delay.
2018-1-19
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