Thanks so much for the info. I'm glad you regularly monitor the threads and always contribute when needed. (and it's often needed)
Compass Error cause or correlation?
- Thread starter Dounin Front
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Frank
There were 3 records on 10/28. I did do 2 flights - the event and one after to see if things were normal again.
No, but in the flt playback in Go it looks like a glitch when the compass error pops up, and the drone jumps to a new location about 100' away. I believe it flew to that location on its own.
Yes it did go on it's own because without gps it doesn't know where it is at. I think it really screwed up that if the aircraft ever gets in the situation that it doesn't just hover in place.
Anyway, the RC data shows your hands or an object moved the sticks at the start. I'm only questioning it due it explaining the a/c's reaction. I know what it looks like is not what took place. It's crazy though.
I did want to ask when you Yaw the direction of the aircraft, is it fast responding? Like if you hold the yaw stick all the way left or right, does the aircraft spin circles fast?
The error flt was possibly the only time I have continuously yawed at full stick. (I keep the stick response set lower for smoother panning) That said, it did rotate faster than I normally see but not quick. I did a couple of rotations in each direction, then few straight out, then lost control, then found atti, then flew back slow, then switched back to P and hand caught it. Then took another flt w/o full stick yaw and it seemed ok. Now I'm ready to try again if the wind will just let up.
I like flying in wind if it is not too violent. One of these days I'm going to after a 30mph tailwind for a new record. However, I ran into my own R/C issue last evening that I need to work on. My A-mode selection stopped working and it's an issue I don't remember ever seeing anyone else mention it.
Btw, the Yaw Setting we spoke about, that is actually different between the two OS's. Android is real fast and takes almost all the setting adjustment to dial it to a slower speed rate. The ios is not bad in comparison to the other OS.
Been away from my PC for a few days.
With the exception of the compass error at time 61 secs I couldn't find anything wrong or unusual about this flight. In particular, the response to control stick inputs was normal (not withstanding my earlier supposition to the contrary). At 61 secs the P3 switched to ATTI and may have appeared to be unresponsive to control stick inputs. But, in fact, the only difference in response was due to the drifting caused by the wind. Just to be clear the P3 entered ATTI on it's own at 61 secs when the compass error occurred. This is different than the pilot switching to A mode on the RC at time 73 secs.
GPS was weak right after launch and before it gained some altitude. After that GPS remained strong and there were no interruptions.
I looked at the .txt and couldn't find any glitches or interruptions that would cause the jump in location that the pilot reports in the Go App playback.
With the exception of the compass error at time 61 secs I couldn't find anything wrong or unusual about this flight. In particular, the response to control stick inputs was normal (not withstanding my earlier supposition to the contrary). At 61 secs the P3 switched to ATTI and may have appeared to be unresponsive to control stick inputs. But, in fact, the only difference in response was due to the drifting caused by the wind. Just to be clear the P3 entered ATTI on it's own at 61 secs when the compass error occurred. This is different than the pilot switching to A mode on the RC at time 73 secs.
GPS was weak right after launch and before it gained some altitude. After that GPS remained strong and there were no interruptions.
I looked at the .txt and couldn't find any glitches or interruptions that would cause the jump in location that the pilot reports in the Go App playback.
Hey Bud
I've flown it 3 times since the error flight - all with no warnings. All good so far. I even did a Litchi WP flight yesterday. Steady as a rock (bad analogy)
Question: My compass was calibrated months ago in the area I usually fly and this flight was normal, except for the multiple rotations (faster than usual). Do you ever see compass errors occurring 75ft or more above the the ground on a flight path often traveled? There are no steel structures near the error location. It is over a pond.
My wife thinks all the yawing probably gave the drone a case of vertigo.
The term "compass error" is used by the DJI Go App to include several different kinds of errors. The Go App will display "compass error" when the nonGPSCause field (in the .DAT or .txt) takes the value SPEED_ERROR_LARGE, YAW_ERROR_LARGE or COMPASS_ERROR_LARGE. (To make it even more confusing, on playback the Go App will present the nonGPSCause error as "GPS lost".) What it's really saying is that the Flight Controller is seeing a value that it didn't predict. Unpredicted magnetometer values are just one example of a nonGPSCause error.
IMHO in this flight the nonGPSCause error wasn't caused by errant magnetometer values. The compass or it's calibration isn't relevant here. As I mentioned above this is like several other inflight nonGPSCause error incidents that I've seen where it starts with an abrupt maneuver. A nonGPSCause error can't be measured directly, it has to be inferred by the Flight Controller. It can't always be correct. It seems that with successive firmware updates there are more false positive nonGPSCause errors. This is a good thing if more actual nonGPSCause errors are caught that would not have been previously caught. I personally have encountered two of these unexplained inflight nonGPSCause errors and have chose to accept them as false positives. A compass error (nonGPSCause error) occurring immediately after launch isn't a false positive. The AC should be recovered immediately. Under no circumstances should a RTH be initiated when a compass error occurs immediately after launch.
It's easy to dismiss your wife's supposition that the yawing 13 secs prior was related to the nonGPSCause error. Maybe you included that has a bit of humor. But, maybe she knows more than some flight analyst wannabes. It might have been a contributing factor. After all, P3s are subject to abrupt maneuvers all the time without a nonGPCause error.
Thank you for the analysis and taking the time to explain it. It looks like a work published in the Northup drone-tech monthly.
I (and my wife) really appreciate your help.
I'll continue to "drone on" albeit a little more smoothly.
The way the Mavic is setup, most of the issues mentioned this thread may not exist.
Is it different than the P4? More redundancies?
I may need a new one in case I have to find my P3 in the brush
Is it different than the P4? More redundancies?
I may need a new one in case I have to find my P3 in the brush
The best advice I could give on the Mavic is to look through and compare the spec sheets, see what the majority of new Mavic owners are saying. The only thing that doesn't appeal to me is the slightly less visual quality.
I have started monitoring the Mavic Forum. I'll have to start following your posts (since I see you have one preordered)
Thanks again for your help.
I got delayed on being able to purchase one, otherwise I would already have it here. I want one asap before dji begins to ruin them like they with each of the other models. I want my a/c to have the firmwares it 1st came out with.
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