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Yaw drift problem and solution

Mavicsailor

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I recently started noticing an issue where if I yawed, then stopped, the Mavic appeared to slowly start yawing in the opposite direction, before it finally stopped 5 to 10 seconds later. This was only appearent when viewing the video with a reference grid, relative to an object in the distance. I could not detect any yaw movement in the AC. At first I thought it may have been caused by the gimbal, but Gimbal drift appears to drift in the same direction as yaw movements as it catches up. I performed various tests to rule out the gimbal as problematic. I performed IMU, compass, RC and gimbal calibrations mutiple times under various conditions with no change. I changed all props with no change. I even downgraded the FW since I first noticed this sometime after the FW upgrade, but with no change.

Further analysis showed that this backward drift after yawing occurred more at some compass points than others. It also occurred more when yawing CW than CCW. Tests were done at both low and higher altitudes, with minimal if any wind. My observations led me to wonder if the compass readings could have been distorted in some way. I ended up taking a fairly strong magnet and waving it in all directions around both the back primary compass and the front secondary compass while viewing the sensor/compass view showing a strong magnetic field. Thereafter I recalibrated the compass and performed multiple test flights. Problem solved!

Interesting that the sensor compass view showed slightly higher average numbers in some directions than others when yawing before the degaussing. After degaussing the average numbers were for the most part uniform when yawing in all directions. These higher numbers also corresponded to compass bearings that were more problematic for backward drift.

As to what caused the compass distortion, I can only guess. Possibly sitting it on top of a laptop while charging. Maybe the magnets in a fan I used to help cool the Mavic got too close during FW updates and other testing. (How long will that little internal fan last?) Magnets are in many devices.

Anyhow..I wanted to share this in the hope that it could help someone experiencing similar "yaw drift" problems, or at the very least create an awareness of where not to sit your Mavic. I would advise if attempting to resolve a similar problem using a magnet to use extreme caution so as to not make the problem worse. At least in my case it saved a trip to the dreaded DJI repair facility.
 
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CyberdyneSystems

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Interesting, I had never considered the on-board compasses picking up a bit of permanent magnetism. There must be some type of ferromagnetic material in or near the compass sensor? Anyway what you did was degauss the sensors by waiving around the permanent magnet; I wouldn't recommend this. It’s more likely than not you would leave behind a magnetized sensor. I’ve use a soldering gun to degauss TV’s and Computer monitors back in the good old CRT days. I imagen you could do the same with the Mavic compasses. On a monitor I would hold the soldering gun close to the screen, pull the trigger and slowly pull it away. The alternating but decreasing magnetic field from the coils would leave the screen with a net zero magnetic field.

 
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Mavicsailor

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Interesting, I had never considered the on-board compasses picking up a bit of permanent magnetism. There must be some type of ferromagnetic material in or near the compass sensor? Anyway what you did was degauss the sensors by waiving around the permanent magnet; I wouldn't recommend this. It’s more likely than not you would leave behind a magnetized sensor. I’ve use a soldering gun to degauss TV’s and Computer monitors back in the good old CRT days. I imagen you could do the same with the Mavic compasses. On a monitor I would hold the soldering gun close to the screen, pull the trigger and slowly pull it away. The alternating but decreasing magnetic field from the coils would leave the screen with a net zero magnetic field.

Yep, I agree. That's why I stated to use extreme caution if attempting to degauss the compass. I could see how it could make it worse if not careful to keep the magnet equal distance/ same pole from the compass in all directions. I used the sensor/compass page to gauge the relative strength of the magnet as I attempted to keep it an equal distance all the way around. In my case, it was worth a try, and the issue is confirmed as resolved after multiple test flights under different conditions.

BTW, interesting use for a soldering gun acting as a degaussing coil. Thanks for pointing this out. I can see how that could work very well.
 
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jljal288

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I recently started noticing an issue where if I yawed, then stopped, the Mavic appeared to slowly start yawing in the opposite direction, before it finally stopped 5 to 10 seconds later. This was only appearent when viewing the video with a reference grid, relative to an object in the distance. I could not detect any yaw movement in the AC. At first I thought it may have been caused by the gimbal, but Gimbal drift appears to drift in the same direction as yaw movements as it catches up. I performed various tests to rule out the gimbal as problematic. I performed IMU, compass, RC and gimbal calibrations mutiple times under various conditions with no change. I changed all props with no change. I even downgraded the FW since I first noticed this sometime after the FW upgrade, but with no change.

Further analysis showed that this backward drift after yawing occurred more at some compass points than others. It also occurred more when yawing CW than CCW. Tests were done at both low and higher altitudes, with minimal if any wind. My observations led me to wonder if the compass readings could have been distorted in some way. I ended up taking a fairly strong magnet and waving it in all directions around both the back primary compass and the front secondary compass while viewing the sensor/compass view showing a strong magnetic field. Thereafter I recalibrated the compass and performed multiple test flights. Problem solved!

Interesting that the sensor compass view showed slightly higher average numbers in some directions than others when yawing before the degaussing. After degaussing the average numbers were for the most part uniform when yawing in all directions. These higher numbers also corresponded to compass bearings that were more problematic for backward drift.

As to what caused the compass distortion, I can only guess. Possibly sitting it on top of a laptop while charging. Maybe the magnets in a fan I used to help cool the Mavic got too close during FW updates and other testing. (How long will that little internal fan last?) Magnets are in many devices.

Anyhow..I wanted to share this in the hope that it could help someone experiencing similar "yaw drift" problems, or at the very least create an awareness of where not to sit your Mavic. I would advise if attempting to resolve a similar problem using a magnet to use extreme caution so as to not make the problem worse. At least in my case it saved a trip to the dreaded DJI repair facility.
I am having the exact same issue, have tentatively tried degaussing compasses but can you elaborate on your procedure on this? Need to know exactly where and how to rotate the magnet in relation to the mavic, a video with a dummy magnet performing the manoeuvre would be very useful!! Also I am going to try rotating my tablet in the controller mount and recalibrate controller, it is also possible that magnets in my tabs leading edge are distorting the controllers movements by impacting the controllers magnetic interference and the controllers behaviour. Fingers crossed, after you degaussed the compasses were the two compass reading much more closely relative to each other when yawing the mavic, my compasses seem to be slightly different, primary compass virtually always less interference than secondary... Finicky machine , solved so many problems with it by tinkering and now just got this yaw drift to sort and think it might be nearly perfect. Thank god for this forum!!
 

Mavicsailor

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I am having the exact same issue, have tentatively tried degaussing compasses but can you elaborate on your procedure on this? Need to know exactly where and how to rotate the magnet in relation to the mavic, a video with a dummy magnet performing the manoeuvre would be very useful!! Also I am going to try rotating my tablet in the controller mount and recalibrate controller, it is also possible that magnets in my tabs leading edge are distorting the controllers movements by impacting the controllers magnetic interference and the controllers behaviour. Fingers crossed, after you degaussed the compasses were the two compass reading much more closely relative to each other when yawing the mavic, my compasses seem to be slightly different, primary compass virtually always less interference than secondary... Finicky machine , solved so many problems with it by tinkering and now just got this yaw drift to sort and think it might be nearly perfect. Thank god for this forum!!
It's been a while, but if I remember correctly the secondary compass is in one of the front legs, and the primary compass is in the rear. If you enter the page in dji Go that shows the Mavic sensors, it shows a number that indicates the current compass readings. These numbers are typically well below 100. As you approach the front and rear compass with a magnet this number will change, allowing you to determine exactly where the compass is. Once this location is determined move the magnet around the compass in all directions fairly close while observing the sensor page to make sure the readings are about th same as you circle the compass. Thereafter, redo the compass calibration clear of anything magnetic.

A clue showing that the compass readings were initially distorted was monitoring the compass sensor reading as I turned the Mavic (no magnetic sources around).The readings were much higher in some directions, than others. This also corresponded to the direction where I saw most of the yaw drift. After I degaussed the compass, the numbers were much more even in all directions while turning the Mavic.

Use great caution before trying this. It worked for me, but no guarantee that others will have the same experience. There are many variables, for example, the distance the compass is from the circling magnet, the strength of the magnet, and the orientation of the magnet. I attempted to keep the magnet direction (pole)pointed toward the compass as circling the compass, so as I was moving the magnet around the compass, I was also rotating the magnet to keep the same pole pointed at the compass. One poster mentioned that he used a soldering gun to degauss monitors. A degaussing method using alternating fields would appear safer.

If nothing else this serves as a lesson to not expose the compass to strong magnetic forces in one direction. I was using a squirrel cage type fan to help cool the Mavic during testing and firmware upgrades while sitting on a table. Later found this fan if too close had a high magnetic influence in one direction (as later observed while monitoring the magnetic sensor page). I suspect this may have had something to do with the compass distortion that lead to the yaw drift in some directions.

On the affects of the R/C on the iPhone (or other). If using the radar compass to help determine the direction of the Mavic from home, moving the magnetic sticks at times can greatly affect the radar compass, disabling its usefulness in determining what direction the Mavic truly is from where you stand. I've never had a problem with the accuracy of the radar compass in DJI Go when using the ipad, or if the iPhone if a distance from the RC. Always a good idea to rotate the Mavic after first taking off to make sure the radar compass agrees with the Mavic direction, and north on the compass radar is accurate. Before taking off, move the sticks in all directions to see if the radar compass is affected....it shouldn't be. The radar compass is the primary tool I use to bring the Mavic home if I loose orientation. It could also be very useful if GPS is lost where the RTH would not work, preventing a flyaway.
 
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jljal288

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Thanks for the tips, my yaw drift seems to be a lot less after calibration and compass one and two seem in closer sync, hesitant to try degaussing again as don't want to mess things up. I will try looking again at how the compass interference numbers change when rotating the mavic, and see if want to try degaussing again, I have improved the yawbdriftnbut its not perfect, see what I can do. Any further thoughts or advice would be greatly appreciated!!
 

darana

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I recently started noticing an issue where if I yawed, then stopped, the Mavic appeared to slowly start yawing in the opposite direction, before it finally stopped 5 to 10 seconds later.
Interesting, I had never considered the on-board compasses picking up a bit of permanent magnetism. ....... I’ve use a soldering gun to degauss TV’s and Computer monitors back in the good old CRT days. I imagen you could do the same with the Mavic compasses.
HOLY #*@*[email protected])$* Thank you both!!!!

My Mavic has been rock solid from day one when I got in April. Got a second one w/ refresh, same, perfect. But my P4P from when I got it in early June has always drifted, since the first flight. It has been a terrible annoyance, often drifting up to 10% of the frame and mine would take 20-80 seconds to calm down! Since I do primarily photography, and a lot of HDR and Pano photography, this was a nightmare. Typically I couldn't even fly straight via the screen b/c the gimbal would be too twisted.

Just got a new P4P for an unrelated issue, SAME PROBLEM. I was honestly about to give up and return it. Then I found your thread. Used the soldering iron. It worked. Both on the ground, hovering in the air, and flying. I had to do 4x 360 degree full speed spins in sport mode to get more than a second or two of drift.

For reference for any others that find this, mine wasn't as regular as what you described, sometimes it drifted towards the yaw, sometimes it drifted away, sometimes it "bounced" drifting with the spin, and then drifting back.

I'm so giddy with happiness right now! Thank you both. I love the Phantom 4 Pro for the incredible camera, but it was getting to the point where it was so frustrating to fly I was honestly not even enjoying it as much or was going back to the mavic b/c at least I could GET a shot instead of watching a gimbal just drift for 60 seconds while my shot moved on.
 

darana

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Sadly looks like I spoke a bit too soon. :( It's always been intermittent but it was more solid than ever for two flights. Last night it was back to its old tricks. Further testing in controlled environments necessary. In the meantime, my Mavic gimbal remains rock solid!
 

SeanOzz

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The ole drunken horizon.
The biggest issue (to me) that the mavic has.
I’ve had three mavics. All with this issue. My current one worked perfectly on 400 firmware and has slightly gotten worse and worse with each firmware upgrade.

It’s still no where near as bad as my original.

My original was slamming down a 24 pack when you would yaw or strafe side to side in any movement at all. Of corse Dji is aware of this issue and takes them back. My most recent mavic only has the camera sway with a side to side motion. The yaw is solid. I’ll probably be sending this one back just before my care refresh runs out next month.

I am seriously hoping the mavic two they focus on this gimbal issue because it was very wide spread on the mavic one.

The Drunken Horizon - With The Mavic Pro - YouTube
 

vili

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My Air yaws slowly while hovering, i cannot make a clear 1-2 sec photo at night.
Made the soldering iron trick, moved slowly above my AC 3-4 times, made compass calibration at the field again, and it still yaws :( Not in all direction, sometimes CW, sometimes CCW, sometimes perfect, sometimes this speed: yaw problem
What else can i do? Latest fw, calibrated everything, etc.
Hardware problem? :(
 

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