Why does the DJI Phantom 3 Compass Hardware Fail?

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Ok, I tried another usb cord...now I'm in business to obtain the dat file. Is there a DAT file reader...or is it txt..
 
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Ok, I tried another usb cord...now I'm in business to obtain the dat file. Is there a DAT file reader...or is it txt..
DatCon can be obtained by going here. You want version 2.3.0. But could you post your .DAT via a Dropbox link? I and maybe some others would also like to look at the .DAT.
 
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Here is the heathydrones link to a flight I'd like to take a look at:
HealthyDrones.com - Innovative flight data analysis that matters

I'll send the DAT file via a google drive link to you Bud via a message. Thanks in advance for any advice. If you are able, I'm curious what the wind speed was computed via the P3A. My theory is at wind speeds near the operational limit causes the P3A to roll or pitch to the extent a few satellites are no longer visible. Possibly a control input aggravates this.
 
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Here is the fly83 file zipped up with the warnings from healthydrones inserted in along the timeline. Interesting to see the yaw errors start at 132 seconds into the flight, compass errors shortly after -right to the end of the flight at 640 seconds.
 

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Here is the fly83 file zipped up with the warnings from healthydrones inserted in along the timeline. Interesting to see the yaw errors start at 132 seconds into the flight, compass errors shortly after -right to the end of the flight at 640 seconds.
Well, I guess you beat me to it. If you snooze you lose.:)
There's something odd about the file you posted. Seems like it began as a .csv generated from DatCon. But, somehow the commas got removed.

I've been developing an app that visualizes the .csv that DatCon or TXTlogToCSVtool produces. It can be obtained here. Here's a plot
upload_2016-7-19_11-33-2.png

NumSats and gpsHealth are plotted with lines. The field nonGPSCause is plotted as the background color of the plot area. Red is YAW_ERROR_LARGE and blue is COMPASS_ERROR_LARGE. These match what HD is calling "Warning:Satellite Positioning Off. Fly with caution". From this plot it's evident that these errors are not related to the GPS. The reduction in numSats and gpsHealth at the end are due to the loss of altitude (the dark red line)

I'm still looking at this to try and determine the cause. So far I've looked to see if there is a correlation between the accelerometer or gyro data and these errors.
upload_2016-7-19_11-31-55.png

upload_2016-7-19_11-31-24.png
 
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This Phantom 3A is going back to DJI for Warranty repair. I'm sure I'm not the only one here with a defective P3A, most items in the warranty are 6 months.
 
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I got my first mid flight compass error today. I did calibration on a beach few hours before flying. I always check Sensors after calibration and it was 1500 +/- 10. I took off from a house terrace and started flying over sea to nearby island. Just a bit over a minute into a flight and some 100 meters away I got red Compass error in DJI Go and P3P started to drift. I didn't panic and managed to get back safely. Although Compass error message went away and status was back to green P_GPS my AC was flying erratically but still controllable if pilot is not in panic mode. The added drama was a very narrow LoS I had for my planned flight path so unplanned drift almost took me away from LoS and probably signal range and with compass error I doubt that my drone would RTH properly. I'm attaching my flight log until I find proper internet connection to upload a .dat file. I would appreciate some insight from forum data miners.
 

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I got my first mid flight compass error today. I did calibration on a beach few hours before flying. I always check Sensors after calibration and it was 1500 +/- 10. I took off from a house terrace and started flying over sea to nearby island. Just a bit over a minute into a flight and some 100 meters away I got red Compass error in DJI Go and P3P started to drift. I didn't panic and managed to get back safely. Although Compass error message went away and status was back to green P_GPS my AC was flying erratically but still controllable if pilot is not in panic mode. The added drama was a very narrow LoS I had for my planned flight path so unplanned drift almost took me away from LoS and probably signal range and with compass error I doubt that my drone would RTH properly. I'm attaching my flight log until I find proper internet connection to upload a .dat file. I would appreciate some insight from forum data miners.
That's scary. If compass go kaput during a long or even mid range flight (no LoS), it can end badly indeed.

Maybe I'm wrong here but I've noticed an increase in such cases, or at least more pilots worried about this Could be coincidence, or could it be that the compass has a limited lifetime and some P3s are now reaching this point and starting compass issues now?
 
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I've had my P3A for three weeks now maybe...

I've had a handful of compass errors, maybe one out of every three flights. I'll be flying along, and the app suddenly announces "atti mode" without me changing anything. When I look down it says compass error. It usually corrects itself within five seconds or so and GPS mode automatically re-engages.

I thought this was a normal characteristic of these drones. In fact, I got a compass error while flying earlier today.
 
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This is my .dat file.I would love some clues about what happened.

FLY100.DAT
I looked at this flight. I can't see any reason for the "compass error" that happened. BTW, it was a YAW_ERROR_LARGE. I won't bore you with all the plots that don't show anything. This flight remained in GPS_ATTI mode the whole flight; it didn't even switch to ATTI during the YAW_ERROR_LARGE event. I even checked the gyroZ drift rate. It was .08 degrees/sec; well within what I typically see. There just isn't anything to see here.

It's been speculated that the recent increase in "compass error" incidents is related to a firmware update. Usually, I'm skeptical of these firmware update explanations because, in IMHO, they rely on anecdotal evidence. But, it does seem plausible that a change has been made that causes the P3 to be more sensitive and be quicker to declare a compass error.

@neven why don't you send the .DAT to DJI and ask them what happened. I'd be interested to see what they say.
 
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I looked at this flight. I can't see any reason for the "compass error" that happened. BTW, it was a YAW_ERROR_LARGE. I won't bore you with all the plots that don't show anything. This flight remained in GPS_ATTI mode the whole flight; it didn't even switch to ATTI during the YAW_ERROR_LARGE event. I even checked the gyroZ drift rate. It was .08 degrees/sec; well within what I typically see. There just isn't anything to see here.

It's been speculated that the recent increase in "compass error" incidents is related to a firmware update. Usually, I'm skeptical of these firmware update explanations because, in IMHO, they rely on anecdotal evidence. But, it does seem plausible that a change has been made that causes the P3 to be more sensitive and be quicker to declare a compass error.

@neven why don't you send the .DAT to DJI and ask them what happened. I'd be interested to see what they say.
First of all thank you for your time and amount of work you contribute to this community.

There is no change to ATTI mode in flight log either. But other then this Yaw error in logs I also have video showing the horizon suddenly tilting maybe 15-20 degrees and since it was no more then few hundred feet away from me I saw that the aircraft tilted to the right (that made me look at my tablet's display and notice red compass error) with camera not compensating. Wind was next to nothing and with no gusts or anything like that.
Sending a log to DJI could be a good idea but my prior experience with them tells me to seek my answers here :). Will do that anyway.


Compass error after a turn @ 1:05. I removed last minute of video because I didn't want you to see me sweating :).
 
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I've had my P3A for three weeks now maybe...

I've had a handful of compass errors, maybe one out of every three flights. I'll be flying along, and the app suddenly announces "atti mode" without me changing anything. When I look down it says compass error. It usually corrects itself within five seconds or so and GPS mode automatically re-engages.

I thought this was a normal characteristic of these drones. In fact, I got a compass error while flying earlier today.
Sounds familiar. I'd get a ticket going with DJI to investigate, one day it will go into ATTI mode at the worst moment. Get it checked out






Sent from my iPad using PhantomPilots mobile app
 
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I got my first mid flight compass error today. I did calibration on a beach few hours before flying. I always check Sensors after calibration and it was 1500 +/- 10. I took off from a house terrace and started flying over sea to nearby island. Just a bit over a minute into a flight and some 100 meters away I got red Compass error in DJI Go and P3P started to drift. I didn't panic and managed to get back safely. Although Compass error message went away and status was back to green P_GPS my AC was flying erratically but still controllable if pilot is not in panic mode. The added drama was a very narrow LoS I had for my planned flight path so unplanned drift almost took me away from LoS and probably signal range and with compass error I doubt that my drone would RTH properly. I'm attaching my flight log until I find proper internet connection to upload a .dat file. I would appreciate some insight from forum data miners.
I searched the uploaded .txt flightlog and found no major issues. The YawErrorLarge is likely due to a bad compass calibration. In the case of issue like that, the P3 will attempt to do part of the process itself by completing a 360 degree rotation. If it doesn't take place by a set time this is when the errors will begin to appear.

Btw, if you should ever happen to calibrate from the area where you're standing in the video, you can expect this error to place. They say nails and screws, and over head roofs can cause issues like this one.
 
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Is there not a warning screen in the Go App that prevents take off with a bad compass calibration? I've seen that screen once when the compass on my P3 was too close to my computer, upon booting up the flight unit, the compass experienced interference from the computer EMF. With the magnetic field strength decreasing by 1/x^3 (x is distance) the effect of most magnetic hot spots will be zero on a passing phantom....unless you pass by a running MRI scanner.
 
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I searched the uploaded .txt flightlog and found no major issues. The YawErrorLarge is likely due to a bad compass calibration. In the case of issue like that, the P3 will attempt to do part of the process itself by completing a 360 degree rotation. If it doesn't take place by a set time this is when the errors will begin to appear.

Btw, if you should ever happen to calibrate from the area where you're standing in the video, you can expect this error to place. They say nails and screws, and over head roofs can cause issues like this one.
Hey Frank.
Compass calibration was done on a beach where those towels are. Nice flat surface, no iron or steel inside pawed surfaces. Sensors were checked after calibration and they were perfect 1500 +/-10 stable. After this flight I did cold IMU, gimbal and new compass calibration and made a flight on a same route from same position. This time there was no compass errors but I had around thirty 1 to 2 sec signal dropouts in a 15 minute flights with AC in perfect LoS and distance between 10 and 1000 meters. I need to troubleshoot this bit more.
 
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Hey Frank.
Compass calibration was done on a beach where those towels are. Nice flat surface, no iron or steel inside pawed surfaces. Sensors were checked after calibration and they were perfect 1500 +/-10 stable. After this flight I did cold IMU, gimbal and new compass calibration and made a flight on a same route from same position. This time there was no compass errors but I had around thirty 1 to 2 sec signal dropouts in a 15 minute flights with AC in perfect LoS and distance between 10 and 1000 meters. I need to troubleshoot this bit more.
If you have perfect LoS at 3280ft you need to consider going to work for the government. :)

Are you using the R/C with stock antenna's only? (the flat side of both antenna's need to face the aircraft at all times)

What altitude was this flight at? (you can achieve a better signal from higher altitudes)

Btw, on your next flight, fly it without using auto launch or auto land. There seems to be issues at times that show up when using that feature. I'm not sure but from what I have noticed in several cases when the pilot launches with auto launch rather quickly it seems to cause a problem. Not every time, just enough to be the one factor that stands out over all others.
 
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If you have perfect LoS at 3280ft you need to consider going to work for the government. :)
I think we are using VLoS if you can actually see your drone. LoS is non-obstructed path from RC to AC. In ideal conditions I can probably spot a Phantom 100m away. And I'm not confirming or denying that I work for government. :)

Are you using the R/C with stock antenna's only? (the flat side of both antenna's need to face the aircraft at all times)
What altitude was this flight at? (you can achieve a better signal from higher altitudes)
Mostly stock (did it that time), sometimes I use basic Windsurfers. I did quite a few 10k+ flights with stock antennas before even some 15k+ ones with Windsurfers equipped. None of them was in such ideal conditions as in this location. Area is almost rural and I was flying off shore with my position over the house in front of me. Started with altitude of 5 meters above starting position (cca. 15m ASL) and went up to 80 meters ASL. I always make sure that antennas are parallel with Phantom "legs". Signal dropouts were on all altitudes.

Btw, on your next flight, fly it without using auto launch or auto land. There seems to be issues at times that show up when using that feature. I'm not sure but from what I have noticed in several cases when the pilot launches with auto launch rather quickly it seems to cause a problem. Not every time, just enough to be the one factor that stands out over all others.
I don't think I ever used auto takeoff or landing (not counting few critical battery autoland heart-stoppers). I take off manually, hoover for 30-60 sec and check if everything works. For landing I use hand catch.
Maybe I'll have some time tomorrow to test the P3P in my home location where I have done most of the flights and can compare date from then and now.
 

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