multiple warnings to calibrate compass and remote disconnection

[redserv]

Hi guys, I experienced some weird errors today while flying (Calibrate Compass and remote disconnect). I will start of by saying that i live in the Caribbean islands and it was very windy today. I visited two sites and got compass calibration errors even after i calibrated on the field. I have attached both the log and DAT file that i saw the wind speed warnings, hopfully this is the correct information. Can someone look into this for me and see if there was anything that could have contributed to the errors? Thanks in advance. ( if i had to guess, maybe the wind was too strong and caused the errors)

 

[Frustrated]

I get calibrate compass every time if fly even when I am flying in the same place. Pain in the butt but O well.

 

[sar104]

The errors were all at the end of the flight, and I can't really see any obvious cause. The compass data look fine, as do the rate gyros, and the IMU yaw and magnetic yaw are consistent throughout the flight. The difference is the magnetic declination at that location (15°), and starts at 3 seconds because that's when the FC gets a GNSS position lock and computes the declination value.



Have you checked the magnetic interference values in the sensor section of the GO 4 app?

 

[redserv]

Hello Sar, first off thank you for helping me out with this. Yes I did check the compass sensors under go4 and it was ok ( green bars). The strange thing is it happened on two different sites while flying. This has me confused. Do you suggest I do an IMU and compass calibration and start from there? I did see your sticky that high winds can cause problems.

 

[sar104]

Hello Sar, first off thank you for helping me out with this. Yes I did check the compass sensors under go4 and it was ok ( green bars). The strange thing is it happened on two different sites while flying. This has me confused. Do you suggest I do an IMU and compass calibration and start from there? I did see your sticky that high winds can cause problems.

This doesn't seem to be causing any flight problems, but no harm doing the calibrations. The errors didn't correspond with large attitude excursions, so I don't think that high winds were the problem. In any case, the wind speeds (< 25 mph) were well within the capabilities of the MP.

 

[redserv]

This doesn't seem to be causing any flight problems, but no harm doing the calibrations. The errors didn't correspond with large attitude excursions, so I don't think that high winds were the problem. In any case, the wind speeds (< 25 mph) were well within the capabilities of the MP.

Ah ok, thanks again, I forgot to mention that because it was so windy I flew in sports mode almost all the time. Forgot to.mention this. I think will calibrate again and monitor this

 

[slup]

The errors were all at the end of the flight, and I can't really see any obvious cause. The compass data look fine, as do the rate gyros, and the IMU yaw and magnetic yaw are consistent throughout the flight. The difference is the magnetic declination at that location (15°), and starts at 3 seconds because that's when the FC gets a GNSS position lock and computes the declination value.

View attachment 95494

Have you checked the magnetic interference values in the sensor section of the GO 4 app?

@sar104 ... It's a lot of erratic IMUCalcs[0] VelocityErrors the whole flight together with continous IMUCalcs[0] PositionErrors from approx 412sec in the DAT.

Also these below is shown especially in the later part of the flight ... don't know what it can mean though ... perhaps nothing that makes this clearer.

 

[redserv]

Hmm, just throwing this out there, I switched out MPP props two flights ago for master air screw props. Could this be causing some extra vibration some how, that's causing other issues?

 

[sar104]

@sar104 ... It's a lot of erratic IMUCalcs[0] VelocityErrors the whole flight together with continous IMUCalcs[0] PositionErrors from approx 412sec in the DAT.

Also these below is shown especially in the later part of the flight ... don't know what it can mean though ... perhaps nothing that makes this clearer.

View attachment 95496

I see the error messages, but I don't see the errors. The IMU velocity error calculations that you are referring to also appear to be incorrect - not sure why. These are the differences between GPS and IMU velocities:



They may look significant, but they are fairly normal, and over a rolling one-second window they both average less than 1 m/s, which is not the case when there are actual velocity errors.

If you look at the GPS and IMU velocities at the end of the flight they agree very well:



This flight was fine in all discernible respects.

 

[redserv]

I see the error messages, but I don't see the errors. The IMU velocity error calculations that you are referring to also appear to be incorrect - not sure why. These are the differences between GPS and IMU velocities:

View attachment 95511

They may look significant, but they are fairly normal, and over a rolling one-second window they both average less than 1 m/s, which is not the case when there are actual velocity errors.

If you look at the GPS and IMU velocities at the end of the flight they agree very well:

View attachment 95509

This flight was fine in all discernible respects.

Hi Sar sorry if it's a stupid question, I just recently switched to master screw props, could this be causing some of my issues?

 

[sar104]

Hi Sar sorry if it's a stupid question, I just recently switched to master screw props, could this be causing some of my issues?

As I said - I've yet to find any abnormal flight data to account for the messages. So perhaps the props did something, but I have no idea what that might be.

 

[redserv]

As I said - I've yet to find any abnormal flight data to account for the messages. So perhaps the props did something, but I have no idea what that might be.

Ok thanks, I will monitor this

 

[slup]

Ok thanks, I will monitor this

Why not switch back to the original, fly for a time & see if the messages stay away ... if they don't show, test the MAS props again. No special setting regarding the MAS on the MPP that you haven't dialed in? Have MAS on my Air & both the Pitch & Yaw Gain setting were recommended a slight adjustment.

 

[redserv]

Why not switch back to the original, fly for a time & see if the messages stay away ... if they don't show, test the MAS props again. No special setting regarding the MAS on the MPP that you haven't dialed in? Have MAS on my Air & both the Pitch & Yaw Gain setting were recommended a slight adjustment.

Yes I think.i will have to go back to the original props then swap back to mas. I am very interested to know if I needed to adjust any special settings on my MPP. Can you or anyone help with this? Thanks again

 

[slup]

The gain settings for my MAS props to the MA came in the box ... if you didn't get any recommendations in your package you probably don't have to change anything.

 

[redserv]

The gain settings for my MAS props to the MA came in the box ... if you didn't get any recommendations in your package you probably don't have to change anything.

Ok thanks again I will experiment with swapping both props stock vs mas and see if I get any random errors. I am thinking that these errors it happened in sports mode, we will see.

 

[Deleted member 114292]

Wait, I thought that calibrating the compass was to account for the drones internal parts and that unless the drone was modded this should not be required again.
My point being that in fact he was seeing magnetic interference, because the DJI warming scrolls that part away.

 

[sar104]

Wait, I thought that calibrating the compass was to account for the drones internal parts and that unless the drone was modded this should not be required again.
My point being that in fact he was seeing magnetic interference, because the DJI warming scrolls that part away.

The drone was modified - he installed additional equipment on top of it.

 

[BudWalker]

@sar104 ... It's a lot of erratic IMUCalcs[0] VelocityErrors the whole flight together with continous IMUCalcs[0] PositionErrors from approx 412sec in the DAT.

Also these below is shown especially in the later part of the flight ... don't know what it can mean though ... perhaps nothing that makes this clearer.

View attachment 95496

The IMUCalcs stuff is computed by DatCon and provides a way to compare the IMU velocities with velocities computed by differentiating GPS position data. The .DAT from a mobile device is only 10 Hz causing the GPS derived velocities to be noisy. E.g., in this flight we have


where the IMU velocity is nice and smooth but the GPS derived velocity isn't. The velocityError data is set to true when the velocity difference exceeds the somewhat arbitrary value of 3.5.

These problems don't occur in the on board .DAT file because the sample rate is higher.

You can also look at the position data obtained by integrating the IMU Velocity data vs. the GPS position data. E.G.


Even better take a look at the GeoPlayer. Here the IMUCalcs path is shown in green and the (mostly) GPS position data is shown in red

 

[redserv]

The IMUCalcs stuff is computed by DatCon and provides a way to compare the IMU velocities with velocities computed by differentiating GPS position data. The .DAT from a mobile device is only 10 Hz causing the GPS derived velocities to be noisy. E.g., in this flight we have

View attachment 95658
were the IMU velocity is nice and smooth but the GPS derived velocity isn't. The velocityError data is set to true when the velocity difference exceeds the somewhat arbitrary value of 3.5.

These problems don't occur in the on board .DAT file because the sample rate is higher.

You can also look at the position data obtained by integrating the IMU Velocity data vs. the GPS position data. E.G.
View attachment 95659

Even better take a look at the GeoPlayer. Here the IMUCalcs path is shown in green and the (mostly) GPS position data is shown in red
View attachment 95660

Thank you guys for the continuous effort to help me with this. Anything different that I could possibly look at than what was said before?