RE: Questions about being level

[LSDMT]

1) how important is it to have the Phantom level when turning it on and letting it go through it’s boot up procedure prior to flight?

2) after it has fully booted up, if you picked it up and carried it over to a clear spot to lift off (which isn’t level) - how important is it it take off from an area that is level?

–

i ask this because on various other machines that i’ve flown, it was super important to boot up from a very level position as that is where the gyros/etc zeroed themselves out. but sometimes out in the field in an unconventional location, there isn’t any place that’s ideally level. on a few occasions, i noticed that the Phantom flew rather weirdly and was harder to land.

 

[KevMo Photog]

1) how important is it to have the Phantom level when turning it on and letting it go through it’s boot up procedure prior to flight?

2) after it has fully booted up, if you picked it up and carried it over to a clear spot to lift off (which isn’t level) - how important is it it take off from an area that is level?

–

i ask this because on various other machines that i’ve flown, it was super important to boot up from a very level position as that is where the gyros/etc zeroed themselves out. but sometimes out in the field in an unconventional location, there isn’t any place that’s ideally level. on a few occasions, i noticed that the Phantom flew rather weirdly and was harder to land.

Good queston LSDMT! I try to get as level as I can at boot up. But after that, then I would think that you could move it to a diff takeoff point and be ok. But def not move it while it's booting up though.

 

[PaulSouthport]

IMU calibration is done "off-line" - by that I mean I you do it as a specific action, not on each boot up. You need to calibrate on a perfectly level surface, but after that, taking off from a sloped surface is not a problem (not too sloped though, it may tip over).

You can pick it up and move it, you may momentarily get a low GPS count by covering the top.

 

[KevMo Photog]

IMU calibration is done "off-line" - by that I mean I you do it as a specific action, not on each boot up. You need to calibrate on a perfectly level surface, but after that, taking off from a sloped surface is not a problem (not too sloped though, it may tip over).

You can pick it up and move it, you may momentarily get a low GPS count by covering the top.

So it's not that critical to be close to level at boot up then Paul? I'm talking side to side level btw. Not front to back.

 

[LSDMT]

Paul - is the ‘IMU Initializing’ then just it turning itself on and remembering the old calibration? you’re sure it doesn’t use any of the ‘live’ info from where it’s booting up from?

 

[Fly Dawg]

Calibration is generally considered a "reference" point where all other related measurements are based on. So yes it does remember the calibrated points. However, in principle it should make no difference in the IMU initialization at power up. BUT, IMHO, and this is based on prior experience, not necessarily with quads, it is wise to base the "power up" point, based on the calibration points. Bottom line, if calibrated on level surface, all things being equal,
initialize as such as close as possible to those points for accuracy. Yes, I know too much info....

 

[Fly Dawg]

One last point on calibration, not for the IMU but for the compass. You do not need to re-cal for every flight. The only exception being where you calibrated last. If you are flying in an area, say within 100+ miles or so of your original calibration, then you may want to consider a re-cal. Other than that you should be fine. Just make sure you check the heading direction in the app before takeoff. Calibrating the compass too often when it does not need to be causes more issues than you may think.

 

[LSDMT]

- noted

 

[N017RW]

Compass cal. is misunderstood and often done much too often.
There really is no arbitrary distance or time since last cal. It comes down to system request or flight performance.
My personal record holder is a P2-NV which was last cal-ed about 2.5 years ago and has been flown 600 miles from that location.
There's no need to take-off on a level surface either. This has no effect on the flight or past cal.

 

[KevMo Photog]

I have not calibrated compass for months now. Flew about 150 miles away from home base once. No issues at all. I agree!