Why does my phantom need to warm up?

[eospro]

Just wondering why the phantom needs to warm up. I have other radio controlled vehicles, some with GPS, Gyro and other sensors and none of them need warming up. Just curious.

 

[msinger]

This video explains the process in more detail:

 

[Squirrel!]

GREAT question and GREAT answer! I never had my P3s need to 'warm up' or ;imu heating up' or any other messages, until I went ahead and, 2 weeks after I had the P3s and many trouble free flights, I discovered I was 'supposed' to calibrate the IMU. Now, virtually every startup has a 'warming up' period that, to me, makes no sense. Regardless, great explanation!

 

[Squirrel!]

And of course the 'warming up' is because I calibrated the IMU in my office which was a toasty 70 degrees, then take it outside to fly, the outside temp is 50 degrees. So the IMU has to 'warm/heat up' to the 70 degrees and that takes some time I'd wager!

So now, the FAS1 is out in the garage where the temp is 35 degrees. Will let it sit there awhile and then do the IMU calibration again. However, I have a question:

Can I do the IMU calibration outside where it is 35 degrees or should I bring it in to the warmth and do the calibration? Which is suggested for optimal results? I imagine the former would be the way to do it, but then again, what do I know.

 

[msinger]

Can I do the IMU calibration outside where it is 35 degrees or should I bring it in to the warmth and do the calibration? Which is suggested for optimal results?

I sit my Phantom outside for ~15 minutes, bring it inside, and start the calibration right away. You could do it outside if you're able to fine a completely level surface where the Phantom will not be disturbed while the calibration is running.

 

[tcope]

I recommend doing an IMU calibration with a temp that is _close_ to normal outdoor temp. I don't recommend a huge variance just to save a little time.

The electronics that make up the IMU take the temp when they are set as the normal operating temps around the Phantom. When the Phantom is turned on later they need to warm up to that temp in order to get correct measurements. So if you set the IMU at 40F and it's 80F outside, there is little warm up needed as the IMU is probably already above 40F. However, this also means that the IMU is going to be calibrated slightly incorrect when when it comes to it's calibrated temp and the outside temp. I've seen no good indication that this presents much of a a problem but a difference IMU calibration temp and normal temps does seen to defeat part of the calibration process.

This is why I'd recommend not lowering the IMU temp a great amount when doing a calibration. A little seems to work just fine and does speed up the warm up process.

 

[msinger]

this also means that the IMU is going to be calibrated slightly incorrect when when it comes to it's calibrated temp and the outside temp

Can you expand on this? What kind of problems has this been known to cause? I've seen a few people mention they believe it causes the altitude to sometimes be off.