Tilted Horizon After IMU calibration

[Brone]

I got a P4P earlier this week. It's my 4th DJI Phantom drone so this isn't my first rodeo

When I first unboxed it I wanted to fly it for a few minutes before calibrating or configuring anything to get a good baseline to go on. I got a Mavic a few weeks ago and it was bad right out of the box. Thats got me action a bit more cautious on this one.

After the first flight I was reviewing the video and was elated by what I saw - PERFECT horizon! As a former P4 owner I really hated the tilted horizon issues. I then ran calibration on IMU, gimbal, etc. - I Setup all my same settings I use on my other DJI drones.

Today I took it out for a flight and it was obvious even just on my iPad mini that I fly with. When I reviewed it on the computer it was even worse.

When I ran the IMU Calibration I was on a VERY level surface. I used a level app on my iPad to make sure it was level and I guess that could have been less than accurate but it was SPOT on level on the screen.

Does anyone have any ideas on what went wrong and what coudl be done to fix it? Once it's back to room temp I'm going to re-run the IMU calibration but I can't imagine that'll make a difference.

 

[UAVNorth.ca]

Did you do the IMU calibration inside or outside?

 

[Brone]

Did you do the IMU calibration inside or outside?

Inside. In the basement on a table that is level.

 

[AlanTheBeast]

When I ran the IMU Calibration I was on a VERY level surface. I used a level app on my iPad to make sure it was level and I guess that could have been less than accurate but it was SPOT on level on the screen.

As an aside, those "level" apps need to be "calibrated" too! (A man with two watches ...)

Seriously a flat floor is all the IMU needs for a calibration. Not in a 140 year old farm house, mind you ...

 

[Brone]

As an aside, those "level" apps need to be "calibrated" too! (A man with two watches ...)

Seriously a flat floor is all the IMU needs for a calibration. Not in a 140 year old farm house, mind you ...

I guess what's important here is - Can a bad IMU calibration cause tilted horizon?

I flew again this evening and flew around quite agressively in the wind. In some of the footage it 'seems' level and it others it's awful and obvious. Tomorrow there is going to be less wind. At that time I'll run another IMU, Gimbal and compass calibration and try again.

 

[AlanTheBeast]

I guess what's important here is - Can a bad IMU calibration cause tilted horizon?

I flew again this evening and flew around quite agressively in the wind. In some of the footage it 'seems' level and it others it's awful and obvious. Tomorrow there is going to be less wind. At that time I'll run another IMU, Gimbal and compass calibration and try again.

I flew yesterday in a stiff breeze - tilted horizon. New P4P. Need to run the gammut...

I suspect there is something not quite right in the gimbal angle software.

 

[Raptorman0909]

Yeah, the level apps on phones are not the most reliable levels one can find and they need to be calibrated to be even remotely close. Use a real level and try again. Also, whatever surface you use needs to be stable and not wobbling around -- a perfectly level surface that's wobbling is worse than a fixed surface that off level by quite a bit.


Brian

 

[Snowwolf]

My horizon level was perfect before the last update, now it's really bad, you can have a level horizon and when you turn the drone it goes badly out of level, so annoying to say the least!!!!!

 

[Raptorman0909]

My horizon level was perfect before the last update, now it's really bad, you can have a level horizon and when you turn the drone it goes badly out of level, so annoying to say the least!!!!!

Did you calibrate the IMU after you updated the firmware? I'm not sure why it should be needed unless the code related to the IMU is changed, but as a rule I perform an IMU and gimbal calibration after every firmware update.


Brian

 

[Traveler]

A thought on calibration issues vs a bad firmware. It would seam logical that if the tilt is always to the left or always to the right, it could be the surface that pilot is using, but if it is sometimes left and sometimes right, (aka, all over the place), then I would think it more likely a firmware issue. Not an expert opinion, just using logic. With regards to surfaces used, I use my solid level pool table, and I always keep the bird at the same verified level local on the table.

One more point, if I obtain a level gimbal, I do not run a calibration after a new firmware update. Now I know that goes against many other opinions, but it's been working for me. In fact I never even calibrate anything without a message to do so.

If it ain't broke, I don't fix it.

 

[Raptorman0909]

A thought on calibration issues vs a bad firmware. It would seam logical that if the tilt is always to the left or always to the right, it could be the surface that pilot is using, but if it is sometimes left and sometimes right, (aka, all over the place), then I would think it more likely a firmware issue. Not an expert opinion, just using logic. With regards to surfaces used, I use my solid level pool table, and I always keep the bird at the same verified level local on the table.

One more point, if I obtain a level gimbal, I do not run a calibration after a new firmware update. Now I know that goes against many other opinions, but it's been working for me. In fact I never even calibrate anything without a message to do so.

If it ain't broke, I don't fix it.

Yeah, a pool table should be a great surface to use: it's backed by a hard surface like slate, it has to be level so the ball travels correctly, and the felt top should provide a bit of vibration damping.

I made a small table with leveling screws and use a precision level to get it level. I then calibrate the IMU and gimbal on it and I've never had an issue with tilted horizon beyond what you should expect if it's really windy or you do a some quick turns.

DJI has the habit of clobbering all/many of your settings whenever you do a firmware update -- why do they not understand that 99.94% of apps/programs are able to perform an update without having to reset all/many of your settings. Seems they could have a table of parameters that do not get clobbered during an update and once the update is complete the new firmware just uses the same parameters as before. The only issue, of course, is that an update may add or remove parameters, but in such a case the parameters that remain the same are left unchanged, the new parameters are set to default and the removed parameters are simply gone.


Brian

 

[AlanTheBeast]

DJI has the habit of clobbering all/many of your settings whenever you do a firmware update -- why do they not understand that 99.94% of apps/programs are able to perform an update without having to reset all/many of your settings. Seems they could have a table of parameters that do not get clobbered during an update and once the update is complete the new firmware just uses the same parameters as before. The only issue, of course, is that an update may add or remove parameters, but in such a case the parameters that remain the same are left unchanged, the new parameters are set to default and the removed parameters are simply gone.

An alternative would be during updates to first copy the parameters onto the computer or phone/tablet doing the update and then to automatically restore them once the update was complete.

A line by line checklist of all parameters would be nifty too.

As to calibration, some before/after data would be nice in order to judge if something has changed.

 

[Snowwolf]

Update of my tilted horizon problem, I performed a VPS but NOT an IMU and now the tilted horizon problem has gone, sorry for time to check but it has been really windy here for a week

 

[KevMo Photog]

Update of my tilted horizon problem, I performed a VPS but NOT an IMU and now the tilted horizon problem has gone, sorry for time to check but it has been really windy here for a week

Hmmm thats cool! Hope it stays gone. I keep calibrating the gimble right before takeoff and have had pretty good luck with that. But man this issue just kinda seems to come and go. It is frustrating but I'm gonna straighten in post anyway. But if your flying a longer one piece flight then it is very frustrating and harder to fix when it comes and goes throughout the flight!

 

[Snowwolf]

I flew with two batteries and kept checking and all stayed good, but I guess it sounds like if could reappear, I will let you know.

 

[Brone]

Just an update on this. I have had and then not-had the tilted horizon issue about 3x since my last post in this thread. I've tried everything listed in this thread and then some.

Sometimes it actually changes mid-flight. Yesterday I took off with it so bad that I could tell when I wasn't even looking at the horizon. Everything over the street/houses seemed tilted. It was the worst I've ever seen it. Then i flicked on sport-mode at about 275 feet and went for a sweet 1,000foot long 50mph cruize with a tailwind. Then when I spun back around and went back to GPS mode -- the tilted horizon was flawless.

I guess we're just going to have to live with this until the next firmware update? There is no rhyme or reason to this at all.

 

[AlanTheBeast]

Just an update on this. I have had and then not-had the tilted horizon issue about 3x since my last post in this thread. I've tried everything listed in this thread and then some.

Sometimes it actually changes mid-flight. Yesterday I took off with it so bad that I could tell when I wasn't even looking at the horizon. Everything over the street/houses seemed tilted. It was the worst I've ever seen it. Then i flicked on sport-mode at about 275 feet and went for a sweet 1,000foot long 50mph cruize with a tailwind. Then when I spun back around and went back to GPS mode -- the tilted horizon was flawless.

I guess we're just going to have to live with this until the next firmware update? There is no rhyme or reason to this at all.

That's interesting. I'll try a buzz next time I see tilted and see if that resets something.

 

[Brone]

This has become a showstopper for me and what I use my P4P for. It's constantly tilted unless I take a semi-violent action and hope that it comes out correct.

The weather has been amazing here the past 3 days and each day I tried to get some stills of the sunset looking right at the horizon. All 3 times after I took off and flew a few hundred feet to where I wanted to shoot the horizion was HORRIBLE. I'm not saying 'tilted' i'm saying it looks like the camera is almost sideways. UNUSABLE.

The only workaround I have figured out is to put it in sport mode and spin it around a few times. If that doesn't work I spin 360degrees to the left the quickly jerk it back to the right for another 360.

When shooting video, if I choose to do anything other than HOVER IN PLACE then my horizon will shift from horrible to slightly-off to unusable to perfect, etc, etc.

I'm pretty mad about the whole thing right now. I think my $1,500 drone should be able to shoot usable video.

 

[GavinW]

Agreed. My P4P is with DJI for the last 4 weeks to get repaired for a severe case of drifting horizon. A P4P that I purchased from Best Buy had it even worse and was promptly returned.

 

[Brone]

I just wanted to post this to let the world know that I still have tilted horizon after trying EVERYTHING. I'm scared to send it to DJI because I don't want a 'refurbished' P4Pro or for them to 'repair' it all to have the same problem or for it to have a new problem in addition to the tilt when I get it back.

I'm just complaining - I don't expect anyone to offer a new solution