Hello All

First I have to say that I'm a newbie to quality drones and DJI. I received the Spark (Fly More) Package for Christmas that included the remote, extra battery, charging station, etc. I connected everything and updated to the latest firmware for both the remote and the Spark. After initial checks, all looked good with IMU and compass but I performed the calibration (compass only) just to make sure.

The first two day of flights were great, I kept it in the beginner mode and stayed around 60-80 feet of max altitude within LOS not doing anything too crazy. All looked good as I was getting use to the controls. That night I noticed that I was getting some firmware update messages again. It was almost like the initial updates didn’t complete correctly. So, I tried again and once more everything looked good. The next morning I decided to fly and the first flight went great as I pushed it up to 200 feet in altitude. The second flight was when I nearly lost the drone as it began to fly erratically away from me about 40 feet off the ground. I was finally able to get it under control and land it across the street in the neighbors yard.

I went in to review the flight in the app to see what happened. at first I see I had GPS (11 tracking?) and that the “Home Point” was recorded and the RTH was set to 60. Then about 40 feet up the mode switches from GPS to ATTI and I got the following warning: “Warning: In Flight, working IMU encounters heading exception,please switch to atti mode if craft behave abnormally”. Almost immediately I get the next warning: “Warning: Weak GPS signal. Positional accuracy may be compromised. Please fly with caution.” At this point I was doing everything I could to get it down without crashing it.

A couple of things about where I am flying. I have been launching it from the grass about teen feet away from cars, house, power lines etc. At the point it went unstable, it was above the house by about 20 feet or so and not near the overhead power lines.

A couple of things to note. I've flow it in this location about 15 times with no issues. I normally let it lift off and hover two or three seconds but on this flight I may have pushed the stick up before it reached the hover off the ground.  After going inside and looking through the software, I got yet another firmware message. Something to do with incompatibilities between modules (sorry I din’t take better notes). Once again I hit update and it completed.

Please understand I take full responsibility as a newbie. I don’t think it was the drone but rather something I did or didn’t do. I just would love some feedback from the vets on here as to what those errors mean and how to prevent them. I got lucky because I really thought it was about to fly away. It really seemed to have a mind of it’s own for a few seconds flying in directions and speeds that didn’t come from me and the remote. The other thing I noticed is that the flight path that was recorded omits where the drone actually flew. I’m guessing this was due to no GPS points.

I survived unscathed and will be ready to fly another day! Any help / advice would be greatly appreciated. BTW I love this little drone!

Are you flying using the RC or directly from your mobile ?   Drifting can't be explained in one step
Most probably you need to do a IMU and compass calib  . But these steps should be done correctly in the sequence depicted in the calibration picture.

Secondly it can also be of strong EMI interference at that moment in time.  

Try flying in a different location before doing any calibration

A lot of "loss of GPS" events are because the spark was launched with the compass locked onto a nearby magnetic source.  The drone will be facing north while the arrow on the map faces south.  As soon as the drone gets high enough to be away from the magnetic interference, the compass swings to true north.  The accelerometers in the IMU say no swing happened so it drops GPS and the drone goes to ATTI mode.  New pilots then lose the drone to fly away because they can't see the drone in the distance in order to control it.

Always check that the DJI Go 4 app's arrow on the map is facing the correct direction when you fly in a crowded area.  And it would be wise to always be ready to fly in ATTI mode as a real pilot would.  Maybe buy a cheap drone that doesn't have GPS and learn to control it?

Gunship9 Posted at 2017-12-28 21:30
A lot of "loss of GPS" events are because the spark was launched with the compass locked onto a nearby magnetic source.  The drone will be facing north while the arrow on the map faces south.  As soon as the drone gets high enough to be away from the magnetic interference, the compass swings to true north.  The accelerometers in the IMU say no swing happened so it drops GPS and the drone goes to ATTI mode.  New pilots then lose the drone to fly away because they can't see the drone in the distance in order to control it.

Always check that the DJI Go 4 app's arrow on the map is facing the correct direction when you fly in a crowded area.  And it would be wise to always be ready to fly in ATTI mode as a real pilot would.  Maybe buy a cheap drone that doesn't have GPS and learn to control it?

Thanks for the reply. For sure I didn’t look to see which way the compass arrow was pointing in regard to actual direction. That’s something that I need to do from now on. As for flying in atti, I have owned several crappy quad copters without gps so I do have some experience with flying. Problem is that at the time of the error messages, the craft didn’t seem to be taking commands from the remote control. I was moving the sticks but the craft continued on its path.

Can spark (or any drone) fly from a location several times successfully and then experience compass interference? Sorry, this gps stuff is new to me!

I fly with compass sensor screen live to check out area.

Madseason Posted at 2017-12-29 09:08
Thanks for the reply. For sure I didn’t look to see which way the compass arrow was pointing in regard to actual direction. That’s something that I need to do from now on. As for flying in atti, I have owned several crappy quad copters without gps so I do have some experience with flying. Problem is that at the time of the error messages, the craft didn’t seem to be taking commands from the remote control. I was moving the sticks but the craft continued on its path.

Can spark (or any drone) fly from a location several times successfully and then experience compass interference? Sorry, this gps stuff is new to me!

You having experience flying in ATTI or RATE modes puts some questions on the Spark not seeming to take commands when the error messages popped up.

Most stories about fly aways have the owner claim it was out of control in ATTI mode but when we look at the flight logs , it shows the craft following the sticks.  One pilot getting ATTI warnings then yawing the craft until it faced him and pulling back on the right stick until it backed away from him into a tree.  He claimed he was controlling it to return to him but it wasn't obeying commands.  I think he couldn't tell which direction the drone was facing and had no ability to control a nose in hover (controls are reversed).

Could your Spark have been flying per GPS errors for a while before calling it a fault and going into ATTI?  It chasing bad data for a time, then dropping into ATTI whereupon you would regain control?

I think it would be something on you that would cause an area to be free of magnetic interference on most flights but cause a compass error on the last flight.  Smart watch?  Phone case with a magnetic belt clip?  Knife case that magnetics closed?  The compass error is the most likely culprit but you could have had a real GPS signal error or the IMU faulting.  

Gunship9 Posted at 2017-12-29 09:54
You having experience flying in ATTI or RATE modes puts some questions on the Spark not seeming to take commands when the error messages popped up.

Most stories about fly aways have the owner claim it was out of control in ATTI mode but when we look at the flight logs , it shows the craft following the sticks.  One pilot getting ATTI warnings then yawing the craft until it faced him and pulling back on the right stick until it backed away from him into a tree.  He claimed he was controlling it to return to him but it wasn't obeying commands.  I think he couldn't tell which direction the drone was facing and had no ability to control a nose in hover (controls are reversed).

Thanks again for all the pointers. I’m pretty sure I had no such things on me that could cause the interference but that is a very good point to remember. Maybe another explanation. As I mentioned, I calibrated the compass but when I did it I was standing about 8-10 feet away from overhead power lines. After reading the manual again I see that’s a no-no. I’m not gonna calibrate again unless it prompts me.

There’s one thing that still doesn’t sit well with me. As I mentioned I am a beginner so I have flown the drown very slowly making only subtle turns . I guess I thought that if the drone lost GPS that It would hover in place (drifting of course) or continue on the path and speed it was flying. In my case the drone made an ubrupt turn and continued in a different direction while picking up speed. I’m 100% positive that it was not responding to any instructions from the RC for about 10 seconds and It was not until gps came back that I could do anything with it. I’m also 100% sure that I didn’t send it on that abrupt turn it made. Flying in atti mode shouldn’t be any different than flying in gps mode from a controller standpoint and I had good control of the drone at the time things went wrong.

Bottom line, I like the drone very much but that experience has me a bit on edge. Its no fun to go out to fly with that in the back of my mind I really appreciate the help and pointers. Hopefully it  will turn out good from here on.

Madseason Posted at 2017-12-29 21:10
Thanks again for all the pointers. I’m pretty sure I had no such things on me that could cause the interference but that is a very good point to remember. Maybe another explanation. As I mentioned, I calibrated the compass but when I did it I was standing about 8-10 feet away from overhead power lines. After reading the manual again I see that’s a no-no. I’m not gonna calibrate again unless it prompts me.

There’s one thing that still doesn’t sit well with me. As I mentioned I am a beginner so I have flown the drown very slowly making only subtle turns . I guess I thought that if the drone lost GPS that It would hover in place (drifting of course) or continue on the path and speed it was flying. In my case the drone made an ubrupt turn and continued in a different direction while picking up speed. I’m 100% positive that it was not responding to any instructions from the RC for about 10 seconds and It was not until gps came back that I could do anything with it. I’m also 100% sure that I didn’t send it on that abrupt turn it made. Flying in atti mode shouldn’t be any different than flying in gps mode from a controller standpoint and I had good control of the drone at the time things went wrong.

You might try switching to sport mode and forcing it back if it starts chasing bad GPS/compass data.  Perhaps it is momentarily chasing the data before dropping into ATTI and your control inputs in normal mode don't over ride attempts to stay in what the bad GPS calls a hover.  

I don't worry about it much and plan on forcing it to the ground it if it gets squirrelly.

I just mess around with what it can do and don't worry if I loose it like all my planes.  Though I do take obvious precautions.  ie, I was going to fly it, with me following and video taping it, across the parking lot and into Best Buy but wasn't sure if the parking lot light poles would cause interference.  So I nixed it.