P3A Compass Issue

Based on the 2 txt flight log files that were attached in post #11 there was NO calibrations that took place. :eek:
well I will have to wait a couple of days - norther blown through north Texas tomorrow and Friday - too much wind to fly.....thanks for looking - interesting the 'calibration' i thought I did apparently just made me look silly in these folks driveway
 
well I will have to wait a couple of days - norther blown through north Texas tomorrow and Friday - too much wind to fly.....thanks for looking - interesting the 'calibration' i thought I did apparently just made me look silly in these folks driveway

Did you know we're waiting on you for the DAT file myself and BudWalker mentioned? Btw, maybe BudWalker's link on details on how to get the DAT file will help you?
 
I thought I had sent those files two different ways - one via dropbox and a second reply by attaching each separate file........
 
Did you know we're waiting on you for the DAT file myself and BudWalker mentioned? Btw, maybe BudWalker's link on details on how to get the DAT file will help you?
Bub apparently was able to open the .DAT files I had previously sent per a previous post - he says the files did not show any calibration and mentioned no other issues - I assume 'no calibration' means the file did not show i calibrated the compass as i had mentioned.
 
I thought I had sent those files two different ways - one via dropbox and a second reply by attaching each separate file........
Please reread P3A Compass Issue The requested .DAT is on the P3, not on the tablet. As that post says this incident is almost certainly due to the concrete rebar. Compass calibration issues are irrelevant. If we can look at the .DAT we'll know for sure.
 
I thought I had sent those files two different ways - one via dropbox and a second reply by attaching each separate file........
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The DAT will appear just like I posted unless you have a Phantom 4 Pro, or a Mavic Pro. Such as FLY141.DAT. It will be the largest of the 2-3 same name files you will see. The DAT file is very large in file size compared to the .txt file. This is why a program like DropBox must be used.

Remember, we're only trying to help you, with no hidden fee's attached.
 
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The DAT will appear just like I posted unless you have a Phantom 4 Pro, or a Mavic Pro. Such as FLY141.DAT. It will be the largest of the 2-3 same name files you will see. The DAT file is very large in file size compared to the .txt file. This is why a program like DropBox must be used.

Remember, we're only trying to help you, with no hidden fee's attached.
I appreciatie it - but I guess i have no idea how to retrieve those files - I tried downloading the flight logs from the aircraft - by connecting the P3A directly to the mac - the aircraft just beeped and created a blank media file - after letting it beep after 10 or so minutes the aircraft made a solid tone with no progress populating the media file - I gave up - the .DAT files I did attach apparently are not the correct ones - those are DJI GO files that are resident on my iPad and retrievable using iTunes and saving back to the PC - they can be opened using Healthy Drones website for example - I appreciate the fact you all volunteered to help - but apparently I am not savvy enough to access the correct files.......
 
Launching at your sidewalk,or driveway should be fine in most cases.
Id be interested in those files. Something else is going on here.
Ive launched, hovered, and flown a P3 over concrete for almost 2 yrs straight with no issues. Including exposed rebar at job sites as well as 30 inch steel drainage pipes. I guess you could call me lucky. :eek:
PS, Majority of concrete sidewalks, driveways, etc do not have rebar. We use a wire mesh in most areas Ive seen in the states. Major roads yes tend to have rebar in them and really no issues reported.
Its usually weight bearing structures like footers, bridges, highways, overpasses that contain a bunch of rebar. Flying around a these items tends not to be a compass issue with most operators.
 
I appreciatie it - but I guess i have no idea how to retrieve those files - I tried downloading the flight logs from the aircraft - by connecting the P3A directly to the mac - the aircraft just beeped and created a blank media file - after letting it beep after 10 or so minutes the aircraft made a solid tone with no progress populating the media file - I gave up - the .DAT files I did attach apparently are not the correct ones - those are DJI GO files that are resident on my iPad and retrievable using iTunes and saving back to the PC - they can be opened using Healthy Drones website for example - I appreciate the fact you all volunteered to help - but apparently I am not savvy enough to access the correct files.......

My 1st thoughts on your response were not that great. But since I do not own or use a mac, it could be the reason you are having trouble? I will say that it totally pointless in mentioning healthy drones with the type of analyzing and the tools we use to do what we do.

I'll tell you something that might help you in this situation or another at some point. But something that might help you is, do searches on youtube to see if someone has info on what it is you are involved in. This might help you see what it is you might be missing.

At this point I'd guess you did not use the GO menu to activate the ability to get to the flight logs. You 1st start with the device, the remote controller, and air craft all Powered up.....and connected to the PC.
 
Thanks to @mjw s persistence he retrieved the .DAT and can take a closer look at this incident. There were actually 2 very similar incidents. Following is the analysis of one of those.

The P3 gets it's heading info from a combination of sensors; mostly the gyros, then the accelerometers. Shortly after batteryOn the Flight Controller initializes the Yaw value based on the compass magnetometers but after that it's info coming from the gyros and accelerometers that determine Yaw. After this the magnetometers have only a small effect on the value of Yaw.

If the launch site is geomagnetically distorted the Yaw value will be incorrect because of the effect on the magnetometers. When the P3 has clears the effects of the geomagnetic distortion the compass/magnetometers become correct, BUT the Yaw is being determined by the gyros which hasn't changed.

That's what happened in this incident.
upload_2016-12-11_5-35-24-png.70576

The P3 was launched from a concrete driveway that contains rebar. magYaw is a diagnostic value calculated from the magnetometers. magYaw and Yaw (the value that the P3 uses for heading) are the same incorrect value until the P3 launches at time 16 secs. Then magYaw (blue line) changes to -127, the correct value, BUT Yaw (green line) stays at the old, incorrect, value of -65. This difference is the reason that a COMPASS_ERROR_LARGE is declared (denoted by the pink background).

The FC should have switched to ATTI mode from GPS_ATTI. The fact that it didn't is the reason it was still tying to navigate using the incorrect Yaw value. If it had switched to ATTI it would have drifted with the wind but wouldn't have been difficult to control. The fact that it didn't switch is very unusual; the other flight did switch.

Unfortunately, checking the magMod value isn't much use in detecting this situation before launch. The geoMagnetic field is distorted but it's strength hasn't changed enough to notice. At the edge of the concrete there may be enough field strength difference to notice. The only way to really detect this kind of problem is to eyeball the P3, know which way it's pointing, and check that with the red arrow in the display. Having said that, I'll also add that I never do this.

The cause of this incident had nothing to do with the compass calibration or lack thereof.
 

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