Litchi Mission Switch to ATTI mode mid mission - P3P

Thanks bsartist. I looked at the two DAT files with CsvView and I saw GPS_Yaw_Error during the ATTI failures from mission mode - in both flights. I don't know what I am looking at, but that may be a clue. Like you said, maybe someone will be able to help solve the problem. I decided to cancel my 6 planned mission for tommorow until I can understand what happened. Could it be an intermittent compass failure. I have not calibrated my compass for the last several flights - all within 30 miles apart. I will play with CsvView tool. Other manual flights that day and the flights back home from the failures, and my test mission the next day all worked fine.
 
Joe, I viewed all of your data for both flights on Flight Log Viewer and also on Air Data with HD Flight Player. My only guess is signal interference. There are 2 towers in the vicinity, the one on the hill you could see and one on the curves on Carefree Hwy. There were 6 drone controllers within 20 feet (not all DJI). Your 1st mission was at 8:09 AM, your 2nd at 10:23 AM. I flew a P4A around the tower on the hill at 9:58 AM with no loss of RC or video. At 10:27 AM, 4 minutes after your 2nd mission, I flew the same mission as my 1st and had disconnect throughout and no video transmission. I'm no expert on radio transmissions but I'm thinking if you shut off your controller the mission would have completed as planned. I didn't experience any of the problems you had. Here is a link to another thread. Litchi waypoint missions never complete - they simply stop mid way
Thanks for the info Charlie.
Joe
 
Thanks bsartist. I looked at the two DAT files with CsvView and I saw GPS_Yaw_Error during the ATTI failures from mission mode - in both flights. I don't know what I am looking at, but that may be a clue. Like you said, maybe someone will be able to help solve the problem. I decided to cancel my 6 planned mission for tommorow until I can understand what happened. Could it be an intermittent compass failure. I have not calibrated my compass for the last several flights - all within 30 miles apart. I will play with CsvView tool. Other manual flights that day and the flights back home from the failures, and my test mission the next day all worked fine.
You shouldn’t calibrate your compass unless told to by the app. There was old documentation that was misleading us into calibrating too often but more recent documentation reverses that myth.

Also distance between calibrations has nothing to do with a need for calibration. Calibration deals with compass deviation. Location deals with variation.
 
Does this mean anything. See attached .jpg
YAW_ERROR_LARGE flight 1.jpg
YAW_ERROR_LARGE during ATTI failure flight1.
 
DAT file dropbox link for flight 1:

Dat file dropbox link for flight 2:
I hope this works.

The switch to ATTI was due to a reported significant yaw error:

ALREADY NaviGo 368.138
YAW_ERROR_LARGE Atti 368.238

Leading to:

368.178 : 25093 [Ctrl<1>] REQ_RC_NORMAL ATTI ctrl_atti

Strangely, however, the yaw and magnetic yaw data don't show such an error:

112310
 
Thank you sar104 for your information. Thus the ATTI event was caused by the large yaw error - not the other way around.

Now what could have caused the yaw error. I don't understand more than one yaw. Doesn't the compass supply the yaw angle? I am trying to understand the plots you provided. Were these plots from CsvView program?

I believe the same event occurred again during flight 2 as well. - large yaw error.

In a hundred missions, (same P3P and tablet) I have never had this happen. Then in one day, it happened in two missions! The events occurred at different areas - not at the same location. What types of things could possibly cause this strange yaw error? After the events, I manually flew back home OK, and also had several other manual flights. All OK.

The next day I flew a 10 minute test mission back at my house, and it worked OK.

Do I have a hardware problem?
Was it interference from the other transmitters flying with me?
How can I test to determine the failure cause?

Thanks for all your help.
Joe
KC7GHT
 
Same thing on flight 2. See the three photos at three different times during second flight. (time=272.41 no error), (time=272.446 GPS_YAW_ERROR), (time=272.514 GPS_YAW_ERROR and ATTI mode entered) See photos below from DAT file flight 2

What signal plot name would show the Yaw Error??

Thanks for all of the help. I sure want to repair what ever is broken!

flight2_1.jpg
flight2_2.jpg
flight2_3.jpg
 
FYI
Did another test mission at home this morning, and it worked on the first mission, but failed again on the second mission. Since it fails at home, that eliminates the thought about the other transmitters at the "get together" with our club, causing the failures.

I am going to fly another P3P (AC and RC) to see if it is in the AC or RC, but still using the same Samsung Galaxy TAB S2 tablet and litchi app:
P3P/Android
Litchi 4.13.0-g

I updated the Litchi App several weeks ago from 4.12 to 4.13, but had 4 successful missions with 4.13 until the first failure.
.
 
Update FYI:

This morning, at home, I flew the spare AC and RC (named MAXWELL). I flew four, 7 minute, 41 waypoint missions. They all worked perfectly.

Then I remembered that on the original (failing) AC and RC (named KAOS), that I had not calibrated the IMU (or compass) in a long time. So I calibrated both the IMU and the compass. Then I decided to get brave and fly the same missions at home that had failed yesterday. I flew four of the 7 minute, 41 waypoint missions and a fifth mission that pushed the AC to climb and dive near maximum rates. All five of the missions worked perfectly!

Did I solve the problem by calibrating the IMU? I may have. Anyway we know the problem was not caused by the other transmitters at the club fly-in, since it failed several times at home. We also know that there was a large Yaw error that happened before the ATTI switch happened - not the other way around. I still don't know which signal name to plot that would show the large Yaw signal error, but both of the DAT file showed this large Yaw error, never the less.

Since I have really had my money's worth out of KAOS (I have 638 air miles on KAOS now), I am going to switch my main AC over to MAXWELL (P3P also). I will still fly KAOS occassionaly as a demo when friends come to visit, and get a few more miles and flight time on him. So we will know after more flights if the calibration of the IMU/compass solved the problem.

Any constructive comments would be helpful.

I hope this information helps.

PS: My wife wants to mount KAOS from the ceiling to remember him by.We have had him over 13,700 feet AMSL, still within 400 feet of the ground, and lots of other places. I said we could do that as long as we don't "stuff" him. Ha Ha.

Thanks for everyones help.
Joe
KC7GHT
 
@sar104,
I just came across this thread.
I still don't really understand what a Yaw error is. But I have understood, that it can be caused by compass and GPS conflict.

Could the OP have a compass issue since it has happened also at his home?

@joeruby,
I got a little confused following this thread.
The problem Phantom, problem ;) has gone away since the IMU and compass calibration?

Yeah, a signal problem I doubt it.

Rod
 
Thank you sar104 for your information. Thus the ATTI event was caused by the large yaw error - not the other way around.

Now what could have caused the yaw error. I don't understand more than one yaw. Doesn't the compass supply the yaw angle? I am trying to understand the plots you provided. Were these plots from CsvView program?

I believe the same event occurred again during flight 2 as well. - large yaw error.

In a hundred missions, (same P3P and tablet) I have never had this happen. Then in one day, it happened in two missions! The events occurred at different areas - not at the same location. What types of things could possibly cause this strange yaw error? After the events, I manually flew back home OK, and also had several other manual flights. All OK.

The next day I flew a 10 minute test mission back at my house, and it worked OK.

Do I have a hardware problem?
Was it interference from the other transmitters flying with me?
How can I test to determine the failure cause?

Thanks for all your help.
Joe
KC7GHT

The compass provides the initial yaw value (heading) at power up, but during flight the primary computation of the yaw value is from the IMU rate gyros. The compass (magnetometer) data are only used at low gain to correct for bias and drift in the rate gyro data - that's why the gyro-derived yaw value can diverge from the compass yaw value.

This could happen if the aircraft flies into an external magnetic field that distorts the earth's magnetic field - for example near a large ferromagnetic structure like a steel bridge. More often, however, it is due either to a distorted field at the takeoff location, resulting in an incorrectly initialized IMU yaw value (most common), or by an out-of-calibration compass where the magnetic field of the aircraft itself produces erroneous compass readings, at least in some directions (less common). Interestingly the Mavic 2 firmware internally corrects for a badly initialized yaw value - if the compass reading changes during takeoff (as the aircraft ascends out of the local distorted field) without the rate gyros detecting any rotation then the FC simply resets the IMU yaw to the new (presumed correct) compass value. That's not how it works with the Phantom firmware however - if the error persists then the FC just switches to ATTI.

However, as I mentioned, there is no evidence of the reported large yaw error in the flight data, so this case is a bit of a mystery to me.
 
@sar104,
I just came across this thread.
I still don't really understand what a Yaw error is. But I have understood, that it can be caused by compass and GPS conflict.

Could the OP have a compass issue since it has happened also at his home?

@joeruby,
I got a little confused following this thread.
The problem Phantom, problem ;) has gone away since the IMU and compass calibration?

Yeah, a signal problem I doubt it.

Rod

See my other reply.
 
Final Update FYI (not necessarily final post).

This morning Joyce and I took KAOS (our P3P) out for another spin. I flew four more waypoint missions at two different locations. All were successful. That is nine successful mission flights since I calibrated the IMU and the compass. Thus I conclude that the ATTI switch problem has been solved, but not understood. It was somehow solved by the recalibration of the IMU and compass. KAOS now has 644 air miles, and nearly 80 hours of air time! Thus KAOS is going into retirement on the shelf in the family room today! Don't worry I have two more unused P3P - MAXWELL and CONTROL.
Again thanks for all those that helped understand what happened.
Joe
KC7GHT
 
Final Update FYI (not necessarily final post).

This morning Joyce and I took KAOS (our P3P) out for another spin. I flew four more waypoint missions at two different locations. All were successful. That is nine successful mission flights since I calibrated the IMU and the compass. Thus I conclude that the ATTI switch problem has been solved, but not understood. It was somehow solved by the recalibration of the IMU and compass. KAOS now has 644 air miles, and nearly 80 hours of air time! Thus KAOS is going into retirement on the shelf in the family room today! Don't worry I have two more unused P3P - MAXWELL and CONTROL.
Again thanks for all those that helped understand what happened.
Joe
KC7GHT
What does KAOS stand for?

Bill
N2ASA
 
What does KAOS stand for?

Bill
N2ASA

Did you ever watch the 1965 to 1969 TV comedy? Years ago I used to enjoy it. KAOS was the evil empire, and CONTROL was the good empire, with MAXWELL and good looking Agent 99 fighting for good against evil. Way-way back when TV was pure and safe to watch.
~~~~~~~~~~~~~~~~
Maxwell Smart, a highly intellectual but bumbling spy working for the CONTROL agency, battles the evil forces of rival spy agency KAOS with the help of his competent partner Agent 99.

Creators:
Mel Brooks, Buck Henry

Stars:
Don Adams, Barbara Feldon, Edward Platt | See full cast & crew »
~~~~~~~~~~~~~~
Oh my, I must be showing my age again.
Joe
KC7GHT
 
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Did you ever watch the 1965 to 1969 TV comedy? Years ago I used to enjoy it. KAOS was the evil empire, and CONTROL was the good empire, with MAXWELL and good looking Agent 99 fighting for good against evil. Way-way back when TV was pure and safe to watch.
~~~~~~~~~~~~~~~~
Maxwell Smart, a highly intellectual but bumbling spy working for the CONTROL agency, battles the evil forces of rival spy agency KAOS with the help of his competent partner Agent 99.

Creators:
Mel Brooks, Buck Henry

Stars:
Don Adams, Barbara Feldon, Edward Platt | See full cast & crew »
~~~~~~~~~~~~~~
Oh my, I must be showing my age again.
Joe
KC7GHT
Oh. Of course I remember Get Smart. And Barbara Feldon who was hot. ;)

I guess I forgot or didn’t know it was spelled KAOS. I guess I thought it was Chaos. LOL.
 
Did you ever watch the 1965 to 1969 TV comedy? Years ago I used to enjoy it. KAOS was the evil empire, and CONTROL was the good empire, with MAXWELL and good looking Agent 99 fighting for good against evil. Way-way back when TV was pure and safe to watch.
~~~~~~~~~~~~~~~~
Maxwell Smart, a highly intellectual but bumbling spy working for the CONTROL agency, battles the evil forces of rival spy agency KAOS with the help of his competent partner Agent 99.
~~~~~~~~~~~~~~
Oh my, I must be showing my age again.
Joe
KC7GHT

One of our UK Freeview channels is currently running Get Smart, along with many other real, clean comedy shows. I “Dream of Jeanie” etc..
Not that I am an aged Puritan or the like but if the random, unnecessary “f” word is comedy then I am an undiscovered comedian. ??

Nothing wrong with showing a bit of age related *crinolines*. < ha-ha-ha! Auto comedy correct!! *crinkliness*

Me? I am a 15 year old teenager ... trapped in the rickle of skin and bone of some 65 year old geezer. At least I still have my handsome good looks. [emoji23]

Cheers, Alan.
 
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FYI:
Maybe I have found the reason why those two Litchi missions, at the fly-in-get-together, failed in ATTI mode! The night before the fly-in, Charlie said to bring my fishing bomb drop attachment. So I bolted on my Gannet fishing bomb drop. It contains some electronics and a battery! (see link below) I simply bolted it on and went flying. Those first two missions failed in ATTI mode.

Now when I first got this device a year or more ago, I bolted it on, and I am sure I calibrated the compass and the IMU and the control sticks. Then went and did a number of tests. After many tests with the bomb drop device, I gained confidence that it did not affect anything. I flew with it for many flights for over a year. No problems. Then I took it off for the Winter, because Joyce was not going fishing this Winter. I am sure I calibrated the IMU and compass again several times during the long time it was off the AC. Now for this fly-in I simple bolted it back on and thought nothing about it. I had the two ATTI failures at the fly-in, and many more ATTI failures during the testing described above in this thread. Until I calibrated the IMU and compass with the unit back on the aircraft. Then the ATTI mode failures stoped!

Could this explain my problem and why it has been solved? In my mind it could be the culprit. Finally explained, and understood.

As always, constructive commence welcome.

See:
 
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FYI:
Maybe I have found the reason why those two Litchi missions, at the fly-in-get-together, failed in ATTI mode! The night before the fly-in, Charlie said to bring my fishing bomb drop attachment. So I bolted on my Gannet fishing bomb drop. It contains some electronics and a battery! (see link below) I simply bolted it on and went flying. Those first two missions failed in ATTI mode.

Now when I first got this device a year or more ago, I bolted it on, and I am sure I calibrated the compass and the IMU and the control sticks. Then went and did a number of tests. After many tests with the bomb drop device, I gained confidence that it did not affect anything. I flew with it for many flights for over a year. No problems. Then I took it off for the Winter, because Joyce was not going fishing this Winter. I am sure I calibrated the IMU and compass again several times during the long time it was off the AC. Now for this fly-in I simple bolted it back on and thought nothing about it. I had the two ATTI failures at the fly-in, and many more ATTI failures during the testing described above in this thread. Until I calibrated the IMU and compass with the unit back on the aircraft. Then the ATTI mode failures stoped!

Could this explain my problem and why it has been solved? In my mind it could be the culprit. Finally explained, and understood.

As always, constructive commence welcome.

See:

OMG, now we get the full story. :)

"Calibration measures the magnetic fingerprint of the surrounding area and on your drone itself."
Posted in this thread.

I really appreciate you posting your findings, so few do.

A lot of us try hard to help others, when it gets figured out we all learn.

Thanks

Rod
 
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