Compass calibration warning

[Skeets]

Hi folks!
First off, I am very meticulous with calibrating my compass, accelerometer, and gimbal. I flew my H about 2 miles away from where initially did my compass calibration. The flight was a non-issue and I had no indication of anything being out of calibration. Howver, upon checking out the Telemetry via UAV Toolbox, I noticed there were several Compass Calibration Warnings. I have done several flights in that location as well as the location that I did the initial Compass Calibration and this is the only flight that has these warnings. The flight in question came maybe 150 feet from normal street power lines but I am not sure whether or not the compass calibration warning coincided at the time the H was near them. Obviously, I will re calibrate everything, but does anyone have a reason as to the warnings, other than the power lines? Should I be concerned? I realize the power lines may be an issue, but surely we cannot be expected to fly no where near any type of power lines (within reason), can we?

Thanks!
Ed

 

[FlushVision]

Hi folks!
First off, I am very meticulous with calibrating my compass, accelerometer, and gimbal. I flew my H about 2 miles away from where initially did my compass calibration. The flight was a non-issue and I had no indication of anything being out of calibration. Howver, upon checking out the Telemetry via UAV Toolbox, I noticed there were several Compass Calibration Warnings. I have done several flights in that location as well as the location that I did the initial Compass Calibration and this is the only flight that has these warnings. The flight in question came maybe 150 feet from normal street power lines but I am not sure whether or not the compass calibration warning coincided at the time the H was near them. Obviously, I will re calibrate everything, but does anyone have a reason as to the warnings, other than the power lines? Should I be concerned? I realize the power lines may be an issue, but surely we cannot be expected to fly no where near any type of power lines (within reason), can we?

Thanks!
Ed

Those warnings came within the last minute of your flight. My experience is that such warnings are not uncommon particularly at the time of landing or taking off. When I look at Telemetry on UAVtoolbox I often see similar.

 

[Skeets]

Those warnings came within the last minute of your flight. My experience is that such warnings are not uncommon particularly at the time of landing or taking off. When I look at Telemetry on UAVtoolbox I often see similar.

Thanks! Do you have any idea why this happens? According the the telemetry, the altitude was in the 30s (meters I assume? Feet?).

 

[FlushVision]

Thanks! Do you have any idea why this happens? According the the telemetry, the altitude was in the 30s (meters I assume? Feet?).

Could be for any number of reasons. The fact that those errors usually happen when the aircraft is coming in to land suggests that the upcoming ground is a factor. I see that the measurements in your picture of your telemetry shows them in feet, so you were 30 feet from the ground and coming in to land.

 

[gwhuntoon]

In the past, I've seen those when operating the landing gear. If you look at the start time and end time for the error, the duration may closely match operation of the landing gear. I think the f_mode field in the telemetry should also indicate that.

 

[Steve Carr]

I frequently see compass errors in telemetry from nearly everyone. They are typically very short. It's only when they become persistent and longer that they become an issue.

 

[PatR]

In the past, I've seen those when operating the landing gear. If you look at the start time and end time for the error, the duration may closely match operation of the landing gear. I think the f_mode field in the telemetry should also indicate that.

Very true. I see a brief compass error every time the gear is cycled and when arming the motors. It may be a brief voltage reduction thing. As mentioned, brief errors are no biggie, it's the long ones we worry about.

That makes me reflect on some fly away reports that occurred at lower battery levels. I wonder if a lower voltage battery can be drawn down by the user increasing power demands to induce a compass failure? Hmmm.

 

[H2O Aviators]

I was getting a compass cal waring while trying to launch off my boat, I calibrated it 6 or 7 times and still got the same error. Each time I calibrated it, it flashed the lights as a success. It wasn't until I noticed I was too close to my subwoofer magnets, that I figured out my issue. Went to the front of the boat, no more warnings. Now, I am very aware of my surroundings when I calebrate.

 

[PatR]

I've often wondered how many people transport their H in a trunk having a sound system or on a back seat between powerful woofers. A compass and a magnet make a bad combination.