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Why does loss of GPS/Compass cause a flyaway?
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hallmark007
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xtro Posted at 2017-7-25 05:48
Yes it moves with the wind, but it does not go away at high speed this is what I meant and the driver can take back the commands, precisely the problem is: what does the spark pass well in atti?
Since the pilots can no longer act on the rc

It will only go to high speed if there is a problem with compass and IMU heading.
2017-7-25
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Stormer
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hallmark007 Posted at 2017-7-25 03:33
Can you upload your flight log to link below, you will get a better understanding of what might have happened. Just click on link below and follow instructions come back here and post your link to your log.

http://www.phantomhelp.com/LogViewer/Upload/

There is something wrong.. I don't see files for 2 today flights in this directory... But I can see them in DJI Go 4 app in Flight Record and play them... where are they located?
2017-7-25
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timothy_tw
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Exact same thing just happened to me about 15 mins ago, I was flying in Gesture Mode but it didn't quite work due to low light, so I took over control manually and flew it forward to increase altitude to about 40m. All of the sudden my Spark started flying backward on its own and despite my enter to correct its course nothing seems to able to stop it from going backward. It finally flew into 2/F parking of my apartment, bump into the wall and crashed upside down, thank god it crashed in the 2/F floor car park, if it were to fall down from that height, I'll be out in the market looking for a new drone by now.

When I picked up my crashed drone, the first thing I notice was the Compass Calibration indicator is in FULL BAR (900+) and it saids it needed calibration (which I did the same morning in the same spot). Given that I was in a car park, I just took my drone and went home. Once I got home I took my Spark out for calibration, and the indicator dropped to 9 (Excellent) without me doing anything, I took the drone downstairs back to that same spot in the car park, Compass Calibration is perfectly normal.
2017-7-25
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hallmark007
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xtro Posted at 2017-7-25 05:48
Yes it moves with the wind, but it does not go away at high speed this is what I meant and the driver can take back the commands, precisely the problem is: what does the spark pass well in atti?
Since the pilots can no longer act on the rc


If Mavic or Spark just looses gps it will react exactly the same as your drone my phantom inspire etc ,as you said it will drift on the wind,

The problems you are reading here are not loss of gps, in fact I haven't seen one case of lost gps, almost 100% of cases report compass interference Imu heading off, and when this happens spark Mavic phantom all these AC there will be a shut down of gps , not a loss of gps and spark will go into Atti mode, by then spark will be off on bad compass direction.

It is very seldom any of these AC lose gps unless under cover of trees or unusual cloud cover.

You need to read the cases around the forum here and see if you can point me to one who had no other problems except lost gps, I will wait patiently for you to find me this case.
2017-7-25
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hallmark007
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timothy_tw Posted at 2017-7-25 07:43
Exact same thing just happened to me about 15 mins ago, I was flying in Gesture Mode but it didn't quite work due to low light, so I took over control manually and flew it forward to increase altitude to about 40m. All of the sudden my Spark started flying backward on its own and despite my enter to correct its course nothing seems to able to stop it from going backward. It finally flew into 2/F parking of my apartment, bump into the wall and crashed upside down, thank god it crashed in the 2/F floor car park, if it were to fall down from that height, I'll be out in the market looking for a new drone by now.

When I picked up my crashed drone, the first thing I notice was the Compass Calibration indicator is in FULL BAR (900+) and it saids it needed calibration (which I did the same morning in the same spot). Given that I was in a car park, I just took my drone and went home. Once I got home I took my Spark out for calibration, and the indicator dropped to 9 (Excellent) without me doing anything, I took the drone downstairs back to that same spot in the car park, Compass Calibration is perfectly normal.

First you could upload your flight log to link below, just click link and follow instructions , come back here and post your link. It will give you a better understanding of what went

http://www.phantomhelp.com/LogViewer/Upload/
2017-7-25
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timothy_tw
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hallmark007 Posted at 2017-7-25 07:54
First you could upload your flight log to link below, just click link and follow instructions , come back here and post your link. It will give you a better understanding of what went

http://www.phantomhelp.com/LogViewer/Upload/

http://www.phantomhelp.com/LogViewer/08MOW2U9VKFEVRE0GH2S/
2017-7-25
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timothy_tw
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timothy_tw Posted at 2017-7-25 08:46
http://www.phantomhelp.com/LogViewer/08MOW2U9VKFEVRE0GH2S/

I lost control twice today, here is the second link and is completely blank...

http://www.phantomhelp.com/LogViewer/8KHG5DP13WB543ASPSYK/
2017-7-25
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hallmark007
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timothy_tw Posted at 2017-7-25 07:43
Exact same thing just happened to me about 15 mins ago, I was flying in Gesture Mode but it didn't quite work due to low light, so I took over control manually and flew it forward to increase altitude to about 40m. All of the sudden my Spark started flying backward on its own and despite my enter to correct its course nothing seems to able to stop it from going backward. It finally flew into 2/F parking of my apartment, bump into the wall and crashed upside down, thank god it crashed in the 2/F floor car park, if it were to fall down from that height, I'll be out in the market looking for a new drone by now.

When I picked up my crashed drone, the first thing I notice was the Compass Calibration indicator is in FULL BAR (900+) and it saids it needed calibration (which I did the same morning in the same spot). Given that I was in a car park, I just took my drone and went home. Once I got home I took my Spark out for calibration, and the indicator dropped to 9 (Excellent) without me doing anything, I took the drone downstairs back to that same spot in the car park, Compass Calibration is perfectly normal.


First you said you did compass calibration before you flew why?

Second you took off with minimum amount of satellites, and during your flight it didn't get any better, I presume you were using you phone or tablet as your log shows no stick movements,
This is one of the first cases I've seen where gps was lost were you flying at night or in an area of high buildings .
Your Aircraft went into Atti mode once for a short time you received a warning, it regained gps you probably should have tried to land, but continued, you lost gps a second time and AC went into Atti mode it's impossible to know if it had any reaction to your control movements as they are not recorded in your log, your aircraft was not moving that fast but was drifting all the time until it crashed.

You really need a minimum of 10 satellites to operate comfortably, you should never fly far on 5,6,7 satellites. I don't use the phone much but I do know if you had RC you could have easily managed to land safely.

Regarding compass asking to be calibrated this is most likely due to your crash, compass was fine until you crashed.



Hope your craft is ok and still flying I will leave a link below that might help with future flights. Good luck.

https://forum.dji.com/forum.php? ... &fromuid=260008
2017-7-25
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hallmark007
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hallmark007 Posted at 2017-7-25 05:50
It will only go to high speed if there is a problem with compass and IMU heading.

Hey xtro one just turned up if you look at log above from ph you will see the transition from lost gps only to Atti mode speed is not very quick and could have with a little bit of experience and RC been controlled easy enough.

This is the point I am trying to make if you have a spark or Mavic and lose gps then it will react exactly the same as phantom or inspire just drift on the wind no speeding away and you are now in Atti mode and can pilot safely but careful.
2017-7-25
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timothy_tw
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hallmark007 Posted at 2017-7-25 09:13
First you said you did compass calibration before you flew why?

Second you took off with minimum amount of satellites, and during your flight it didn't get any better, I presume you were using you phone or tablet as your log shows no stick movements,

Hey, thanks for your reply, I really appreciate you insight!

This is one of the problem of flying a drone in Hong Kong, it is impossible to avoid buildings here man (the most vertical city on the planet is no joke).

My question is, once it enters Atti mode, shouldn't I have full control over the Drone? Why does it keep going backward (it wasn't drifting) when I'm not touching the stick (virtual) at all?

Cheers mate.
2017-7-25
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hallmark007
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timothy_tw Posted at 2017-7-25 09:37
Hey, thanks for your reply, I really appreciate you insight!

This is one of the problem of flying a drone in Hong Kong, it is impossible to avoid buildings here man (the most vertical city on the planet is no joke).


It keeps going on the wind it may well be making its own wind so looks like it's going backwards because gps is what keeps your AC hovering in place and it was not strong enough signal, it shouldn't lose height unless it crashes and it didn't according to your log, height is managed by VPS up to height of 26 feet and barometer up to 500 meters or its limit , but when it goes into Atti mode your virtual control movements need to be very positive almost twice as much as they would to control AC in gps mode.
2017-7-25
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fans0056fba7
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Maybe I'm misunderstanding this , but the problem with the aircraft switching to ATTI mode and flying away seems to have more to do with Pilot abilities then it does with aircraft function. In ATTI mode you must actively pilot the drone I.E. its going forward, you need to pull it it back, its drifting left you need to correct with right input, and the drone will not auto correct itself,  This becomes an issue when you have a large group of novice pilots buying these GPS controlled aircraft, they have never actually had to pilot an RC aircraft before, so when a malfunction happens and the aircraft switches to full pilot control, combine this with flying on a phone which means you have limited range and time to correct an issue .......... Fly away.
2017-7-25
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hallmark007
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fans0056fba7 Posted at 2017-7-25 10:01
Maybe I'm misunderstanding this , but the problem with the aircraft switching to ATTI mode and flying away seems to have more to do with Pilot abilities then it does with aircraft function. In ATTI mode you must actively pilot the drone I.E. its going forward, you need to pull it it back, its drifting left you need to correct with right input, and the drone will not auto correct itself,  This becomes an issue when you have a large group of novice pilots buying these GPS controlled aircraft, they have never actually had to pilot an RC aircraft before, so when a malfunction happens and the aircraft switches to full pilot control, combine this with flying on a phone which means you have limited range and time to correct an issue .......... Fly away.

No malfunction occurs in the aircraft, its loss of gps which is outside of aircraft. Yes it needs full pilot control, and yes training will help you could buy any small drone for $50 and practice Atti mode and this is probably the best way to do it.

When AC loses gps it is still quite controllable it won't lose height, but probably best move would be to raise AC to open sky where your chances of receiving gps are increased, I haven't experienced Atti mode with virtual control but can imagine it's a bit more difficult. Yes you will be very active on the controls but it is doable, don't panic and be aware.

As the RC pilot you can do a few things to avoid this happening, fly in suitable environment, don't just push the up throttle, wait for sufficient gps lock monitor it while flying and always before you take off have a number of safe places to land if your in trouble
2017-7-25
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Stormer
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I finaly managed to upload my log from fly away..
http://www.phantomhelp.com/LogViewer/02LBWVTXVEF1VLDNGA2F/

Someone can analyze what was wrong?

Log is from mobile phone so it ends when connection with Spark is lost forever////
2017-7-25
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hallmark007
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Hi stormer, looking at those logs it first shows yaw error these are usually associated with magnetic interference and will show on your dat file which is in your Aircraft as magyaw so some sort of magnetic interference, it could have been picked up when you were taking off or from something you were flying over, but most likely from take off some metal in the ground or rebar concrete will do it,

It has the effect of AC compass taking off in a direction gps does not want to go it becomes so strong that basically gps gives up and AC goes into Atti mode, by this stage AC is free flying and only having use of virtual sticks almost impossible to control so hence your crash.

There are ways to try avoid this happening I will leave link below. There have been a few cases like this with spark. Is it pilot error I wouldn't like to say. I don't think many pilots could exhume control of this sort of thing.
But in some of the cases I have seen dji have offered warranty, I would send craft back for analysis dji will be able to tell more from dat file in black box of drone.

I wish you luck my friend.

https://forum.dji.com/forum.php? ... &fromuid=260008
2017-7-25
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PascalG
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eylneb Posted at 2017-7-21 09:10
mobile phones dont just rely on GPS to get actual coordinates..

it uses cell tower, gps & even wifi to get accurate readings....

Not true...  I regularly use gps on my phone and iPad in locations with no cell and no wifi and the iOS based gps is as accurate as marine systems costing thousands of dollars....

I have logged tens of thousands of miles running both a marine system and my iPad as a back up and the iPad has never been off compared to the expensive marine system.
2017-7-25
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hallmark007
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PascalG Posted at 2017-7-25 11:27
Not true...  I regularly use gps on my phone and iPad in locations with no cell and no wifi and the iOS based gps is as accurate as marine systems costing thousands of dollars....

I have logged tens of thousands of miles running both a marine system and my iPad as a back up and the iPad has never been off compared to the expensive marine system.

Mobile phone is not up to the minute reliable just try walking with it using a map and see if the red dot falls behind if it does then that's because receiver in mobile is cheap.

If it's as accurate as your marine system then you might advise marine to get there's checked our.
2017-7-25
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Stormer
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hallmark007 Posted at 2017-7-25 11:12
Hi stormer, looking at those logs it first shows yaw error these are usually associated with magnetic interference and will show on your dat file which is in your Aircraft as magyaw so some sort of magnetic interference, it could have been picked up when you were taking off or from something you were flying over, but most likely from take off some metal in the ground or rebar concrete will do it,

It has the effect of AC compass taking off in a direction gps does not want to go it becomes so strong that basically gps gives up and AC goes into Atti mode, by this stage AC is free flying and only having use of virtual sticks almost impossible to control so hence your crash.

thanks for analysis..  don't know why that magnetic interference happend... was starting from center of meadow in center of big park where only trees are around and it happend in 50m where is nothing... I hope it will not happen again.. thanks a lot a have sent black box and DAT log file to DJI... I will wait for reply before next flight
2017-7-25
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PascalG
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hallmark007 Posted at 2017-7-25 11:43
Mobile phone is not up to the minute reliable just try walking with it using a map and see if the red dot falls behind if it does then that's because receiver in mobile is cheap.

If it's as accurate as your marine system then you might advise marine to get there's checked our.

depends on the app.  some do not refresh the dot on map as often as the built in GPS receiver updates the position. Some apps do... but the actual GPS chip set is as good as anything else.
2017-7-25
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hallmark007
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Stormer Posted at 2017-7-25 11:52
thanks for analysis..  don't know why that magnetic interference happend... was starting from center of meadow in center of big park where only trees are around  and it happend in 50m where is nothing... I hope it will not happen again.. thanks a lot  a have sent black box and DAT log file to DJI... I will wait for reply before next flight

Ok let's us know outcome.
2017-7-25
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hallmark007
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PascalG Posted at 2017-7-25 11:53
depends on the app.  some do not refresh the dot on map as often as the built in GPS receiver updates the position. Some apps do... but the actual GPS chip set is as good as anything else.

I do agree they are great especially for their size, just pulling your leg a bit.
2017-7-25
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eylneb
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PascalG Posted at 2017-7-25 11:27
Not true...  I regularly use gps on my phone and iPad in locations with no cell and no wifi and the iOS based gps is as accurate as marine systems costing thousands of dollars....

I have logged tens of thousands of miles running both a marine system and my iPad as a back up and the iPad has never been off compared to the expensive marine system.

Noted.. I'm no expert anyways...

http://www.macworld.com/article/ ... location-works.html
2017-7-25
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Stormer
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Update for my fly away:

DJI tech support said to send my Spark to repair team, because "Yaw Error" is some internal error and have to be inspected by DJI....
2017-7-26
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