Hi all,

It was a gorgeous morning, I was on holiday, and thought I would take my spark up for a few nice videos. It took a while, and eventually there were sufficient satellites to take off. I launched, and flew really near by with my controller. After about 45 seconds, while trying to get a steady shot, no wind, the drone started to go in a different direction. It started to veer off, and my controller started beeping. I saw the direction it headed, I tried to get control back, but it just flew away. Controller just kept beeping.

I checked how to find a lost drone. Took a walk to the exact position, looked all around, and there is no drone. Been hunting for it, but I can't find it. Reviewed the logs on my phone, and it doesn't show much.

Any idea what can be done. We're leaving back home tomorrow, and haven't got much more time to look for it.

I will never be able to buy another drone after this, so really want to find it.

Not sure how to get the log from my phone either.

Any help will be appreciated.

Hi, sorry for the inconvenience. Please contact our support (https://www.dji.com/support?site=brandsite&from=nav) so that we can investigate on this issue. Our support will ask you to sync your flight records on your DJI Go 4 app. Please do not delete or uninstall the app because we will use it to investigate on your case.

Try looking in your Video Cache on your Phone to see where it went, maybe it is Stuck in a Tree or in Landed in High Grass.

If the Controller was Beeping you have Hit RTH or it lost connection with your Controller and started RTH Automatically.

Goodluck in Finding it.

Upload your Flight Records here so you can receive help - http://www.phantomhelp.com/logviewer/upload/

DJI Paladin Posted at 2018-6-30 07:35
Hi, sorry for the inconvenience. Please contact our support (https://www.dji.com/support?site=brandsite&from=nav) so that we can investigate on this issue. Our support will ask you to sync your flight records on your DJI Go 4 app. Please do not delete or iuninstall the app because we will use it to investigate on your case.

Thank you. That is reassuring. I have logged a call, and I will await a response.

Here is my flight record - http://www.phantomhelp.com/logviewer/4YBY0RJKZA5OZH4AK6S2/

Nilesh-spark Posted at 2018-6-30 08:04
Here is my flight record - http://www.phantomhelp.com/logviewer/4YBY0RJKZA5OZH4AK6S2/

Thanks Nilesh -

1m 8.5s        Auto Landing        12satellites        110.9ft        N/A        0.9mph        377.4ft        82%        11.252V        3.771V        3.759V        3.722V        0.049V        Yaw Error

You took off with a Weak GPS and not so many Locked Satellites. Always check you have at least 11 Satellites and the GPS Signal Bars is Strong.

The Trees may have caused the Disconnection between Remote and Spark as they do a lot of Interference.

Most Probably at that Height it Autolanded in some Trees. Its like a Mini Forest there.

You have to go in that Area and Search for it, it will be there but you need Patience. From here no one will tell you exactly the Point where it is. Look in those Trees.

DMX_MT Posted at 2018-6-30 08:10
Thanks Nilesh -

1m 8.5s        Auto Landing        12satellites        110.9ft        N/A        0.9mph        377.4ft        82%        11.252V        3.771V        3.759V        3.722V        0.049V        Yaw Error

Before losing connection, there was direct line of site of the drone, without any trees in the way to cause interference.  It was really close, and did not want to fly it too far out. I just wanted a shot of my immediate vicinity. Only once it lost connection, and started to fly off, did go towards the heavier forestry.

Ahh well, I really appreciate your support. My heart sank when it took off on it's own, and it's gone. I'll go have another look tomorrow, but I hunted today.

You're really helpful. Thank you.

Nilesh-spark Posted at 2018-6-30 08:18
Before losing connection, there was direct line of site of the drone, without any trees in the way to cause interference.  It was really close, and did not want to fly it too far out. I just wanted a shot of my immediate vicinity. Only once it lost connection, and started to fly off, did go towards the heavier forestry.

Ahh well, I really appreciate your support. My heart sank when it took off on it's own, and it's gone. I'll go have another look tomorrow, but I hunted today.

Good luck Brother, look in the Trees and High Grass. It is there for sure as it did an Autolanding.

Hi Nilesh,

Sorry for your loss!
Had a look at your flightrecord too, in the file is written that this whole flight has been recorderd on video. So if the landing is on video mayby you see some reference points where to look.
The flightlog shows only at the end a disconnection, so mayby only your Go 4 app stopped working at certain point? Just curious to understand it better.
Another question ; did you press the autolanding button (and slide to accept) in the Go 4 app ?

Hope you will find your Spark.

cheers
JJB

There is that YAW issue again

Looks like it may have landed in an open space... or at least ground level vegetation... that looks like a right of way on the map....

pmshop Posted at 2018-6-30 12:41
There is that YAW issue again

Hi pmshop,

This time it started with a compass error, but in the Spark system Yaw, Speed and/or Compass errors ends mostly in an ATTI mode.

cheers
JJB

JJBspark Posted at 2018-6-30 13:03
Hi pmshop,

This time it started with a compass error, but in the Spark system Yaw, Speed and/or Compass errors ends mostly in an ATTI mode.

Checked if HomePoint is where Spark is?

This seems to be Homepont's mistake and the Spark RTH performs: The remote control goes off, goes to Spark and the log Autolanding is over. If you are in RTH mode, you can move the joystick in vain. The RTH must be discontinued to recover manual control.

Do the few satellites cause the HomePoint to be in the wrong place?
I guess so also says a female voice: "Homepoint is updated, please checking on the map!"

I'm new to reading these logs, so pardon me if this is a dumb rookie question. At 19.9 seconds, log reads "Home point recorded". At 45.5 seconds, it says "GPS signal too weak. Home point not updated". Why did HP need to be updated when it was already recorded?

Jakab Gipsz Posted at 2018-6-30 14:17
Checked if HomePoint is where Spark is?

This seems to be Homepont's mistake and the Spark RTH performs: The remote control goes off, goes to Spark and the log Autolanding is over. If you are in RTH mode, you can move the joystick in vain. The RTH must be discontinued to recover manual control.

Believe it or not you still have altitude control in RTH.
On this RTH, I wanted to skim the surface, but the 30m minimum RTH altitude prevented me:
Time marker 0:42 on, you see the the craft dip and then return to RTH

Did you try using the Find My Drone option in the DJI GO 4 App?

Sorry for your loss, mate. Try and look for it again in this area.


Other than that provide DJI support with whatever they ask for, I'm confident you will get a replacement. Good luck!

Jakab Gipsz Posted at 2018-6-30 14:17
Checked if HomePoint is where Spark is?

This seems to be Homepont's mistake and the Spark RTH performs: The remote control goes off, goes to Spark and the log Autolanding is over. If you are in RTH mode, you can move the joystick in vain. The RTH must be discontinued to recover manual control.

Hi Jakab,

I have seen this HP issue as well, if the number and reception of sats is low Spark doesn`t set HP.
This means when you fly away in that situation Spark set HP during flight when there are enough and good reception of sats ; meaning that HP is not where you are at takeoff point!!
Big problem if you activate RTH and Spark fly to this other HP position.
In this flight it was close to the actually takeoff point.

If there is a disconnect > 3 seconds the flightmode changes into GoHome. Not in this case. I am puzzled why this Spark went into autolanding. In ATTI mode and no connection Spark will autoland, but in this flight at the time of autolanding the connection was present.

cheers
JJB

Prairie Chicken Posted at 2018-6-30 16:59
I'm new to reading these logs, so pardon me if this is a dumb rookie question. At 19.9 seconds, log reads "Home point recorded". At 45.5 seconds, it says "GPS signal too weak. Home point not updated". Why did HP need to be updated when it was already recorded?

Hi Prairie Chicken (oops, never saw one can we see a picture please? )

I think that DJI uses the same message for multiple situations.

If at startup this msg is shown ; OKE, good info that HP is not set/updated.
If during flight the GPS signal becomes weak ; OKE, do inform me but skip that update part.

If HP is set at the start of the flight if will no change during flight, unless you do change it yourself.
(or if it is a dynamic hp when in tracking mode)

cheers
JJB

Nilesh,

You started your flight without home point locked.
Home Point was recorded later, about 20 metres NE of your starting position over something which looks like large tree overlooking a pond.

You say that there was no wind. At 30 metres of altitude pitch and roll of Spark is consistent with either gusts of wind from NW or uncalibrated IMU.

Did you calibrate IMU and compass?
Are there any obvious sources of magnetic or electro-magnetic interference nearby (high power lines, cell towers)? I cannot see from Google maps.
Did you start from a concrete pavement which may have had steel bars in it?

If you did calibrate IMU and compass and are certain of no interference nearby (even from your cellphone which could have been too close when Spark was starting), you may have a case for a warranty replacement. Spark’s navigational system got out of whack and Spark dropped to ATTI.

While in ATTI it started to fly away pushed by gusts of wind at 34 metres altitude.

During fly-away you do have contact with the AC but logs show that you do not try to rescue it.
It looks like you are watching, frozen, while Spark flies away.
At some point you start raising Sparks altitude (I see you throttle stick moving forward) – and Spark obliges – it means that it does listen to your commands.

Logs also show big differences between IMU calculated and GPS calculated speed. This may be consistent with IMU failure or total confusion.

It seems you may have lost signal with Spark around 1 minute 4 seconds because it starts landing procedure to avoid being blown off the course even more.
I suspect that this is when your RC started beeping. I also suspect that by this time you did not see Spark because the angle from where you are standing and where the Spark is shallow and it is possible that Wifi signal was blocked by trees.

Your Spark is auto-landing with a speed of about 2m/s while being blown SEE with a speed of about 5 m/s. With 34 vertical metres to go at the position where logs end, it will take it about 12-16 seconds before it will hit the trees in its descent (depending on tree height). You should look for it in the direction of the red line about 60 – 90 metres away from the last point on the map where the communication ends.

I believe @antipaxi map where to look for Spark was close but not quite right. See map I pasted below.

In summary: If compass and IMU was calibrated and there was no interference at ground level or higher up, I expect Spark's systems failure causing it to drop to ATTI. DJI will need to check.

I am very interested to hear from you if any of what I said above does not agree with what you observed or did on the ground.

Good luck in your search!

Mirek

Mirek6 Posted at 2018-7-1 07:40
Nilesh,

You started your flight without home point locked.

Hi mirek,

I never saw a flightrecord where its started an autolanding in ATTI while not disconnected.

Wich component / algorithm in a Spark thinks "well i am in ATTI  mode and the wind is blowing me away, lets go into autoland" ? Mayby an OP action?

This in btw a great example of flying away with no HP set and during flight HP is set. This time only 20 meters away from take-off point. If more than the OP ask why doesn`t it return to HP....

cheers
JJB

I was thinking, the moment you get tons of error messages and the AC goes to ATTI, as a new or fairly new pilot, your instinct is to press RTH. I think the better choice would be to press DOWN DOWN DOWN, to keep the AC away from the high winds, and, if the AC is responsive, get it as low as possible and then as close to you as you can.

JJBspark Posted at 2018-6-30 12:32
Hi Nilesh,

Sorry for your loss!

Hi, thank you for your help. There was no issue with the app. The app stayed on for the duration of the flight, even after it lost control. I did try to push the auto landing button, but it was too late. It was out of sight fairly quickly.  

I hunted again today, and still, could not find it. Had to return home from holiday. It's gone!!!!

pmshop Posted at 2018-6-30 12:41
There is that YAW issue again

This yaw error .. my word. It's horrible.

Northwood Posted at 2018-6-30 12:47
Looks like it may have landed in an open space... or at least ground level vegetation... that looks like a right of way on the map....

I hunted, spent the better part of 4 hours on a weekend getaway looking around for the drone.  Took the kids too, and nothing.

JJBspark Posted at 2018-6-30 13:03
Hi pmshop,

This time it started with a compass error, but in the Spark system Yaw, Speed and/or Compass errors ends mostly in an ATTI mode.

Thanks. It does look like that. Not sure why though. This detailed log looks quite technical.

Jakab Gipsz Posted at 2018-6-30 14:17
Checked if HomePoint is where Spark is?

This seems to be Homepont's mistake and the Spark RTH performs: The remote control goes off, goes to Spark and the log Autolanding is over. If you are in RTH mode, you can move the joystick in vain. The RTH must be discontinued to recover manual control.

Yes, I checked. but no spark located. I went to the last location, and used the find my drone option.

Prairie Chicken Posted at 2018-6-30 16:59
I'm new to reading these logs, so pardon me if this is a dumb rookie question. At 19.9 seconds, log reads "Home point recorded". At 45.5 seconds, it says "GPS signal too weak. Home point not updated". Why did HP need to be updated when it was already recorded?

This is a good question. I didn't understand that myself. It usually records the home point on take-off. I took off, and the home point was recorded a few seconds later.

davidmartingraf Posted at 2018-6-30 20:08
Did you try using the Find My Drone option in the DJI GO 4 App?

Yes, I did. I went to the location and searched all over for 4 hours. Nothing.

Antipaxi Posted at 2018-6-30 21:04
Sorry for your loss, mate. Try and look for it again in this area.
[view_image]

Thanks man. I appreciate it. I spent about 4 hours searching the location. I went around and around, and came up with nothing. Logged a support call with DJI. Let's see what comes of it.

Mirek6 Posted at 2018-7-1 07:40
Nilesh,

You started your flight without home point locked.

Hi,

Thanks for your help.  I did not calibrate the IMU or compass before I took off.  However, there was no concrete where I took off from. I took off from paving.  It was in a forest, and there wasn't much electromagnetic interference that I could tell. Did not notice any cell towers.

While I felt a bit of disbelief when it started drifting off, I did try to rescue it. I used the controller, I even tried to put it in sports mode and back to normal mode to regain control. But it just kept going until it went our of sight behind the lodge at which I was staying. I then tried to return to home immediately, but the app said signal lost, and started to beep. It all happened really quickly, and between running to keep my eye on the drone and direction, and trying to steer it, it was gone within 5 seconds.

I did have a look for the drone in the vicinity of your marker, and after 2 hours of looking yesterday and 2 hours today, I had to give up.

The drone is gone.

JJBspark Posted at 2018-7-1 08:05
Hi mirek,

I never saw a flightrecord where its started an autolanding in ATTI while not disconnected.

Exactly. It should have returned to home point. And there wasn't much wind at all.

Antipaxi Posted at 2018-7-1 08:14
I was thinking, the moment you get tons of error messages and the AC goes to ATTI, as a new or fairly new pilot, your instinct is to press RTH. I think the better choice would be to press DOWN DOWN DOWN, to keep the AC away from the high winds, and, if the AC is responsive, get it as low as possible and then as close to you as you can.

While I understand that there may have been a little wind, it was really not a very windy morning.  I did try to get control before using the RTH feature. I did try to bring it down, but it was all over really quickly. Loss of control, compass error, and drone out of sight - felt like under 10 seconds.

Nilesh-spark Posted at 2018-7-1 08:48
Exactly. It should have returned to home point. And there wasn't much wind at all.

Nilesh,

You say:"
Exactly. It should have returned to home point. And there wasn't much wind at all"

In ATTI the drone will not return to home point.
Home Point was set correctly 20 metres from where you took off - granted. But then series of errors happened throwing off Spark's flight controller. Once you drop to ATTI, you need to take manual control.

I have seen many situations where you do not feel any wind at the ground level (you were in trees) and  where the gusts may occur at higher altitudes. Spark is very light and in ATTI can be blown by a puff of air. It happens to me all the time when I fly indoors.

Your Sparks attitude show either a slight wind from NW or IMU issue with keeping Spark level.
However, when I look at fly-away pattern and attitude during flyaway, it is consistent with being pushed by irregular breeze rather than IMU issue.

Nilesh-spark Posted at 2018-7-1 08:35
This is a good question. I didn't understand that myself. It usually records the home point on take-off. I took off, and the home point was recorded a few seconds later.

Hi Nilesh,

Let me explain about setting the HP. HP is set by Spark if the GPS signals and reception are OK.
You took of with low sat count and bad reception, no HP is set.
The moment during the flight when signals are ok, spark will set the HP. In your case this happend 20 meters away from your homepoint.

That`s why it is so important to takeoff when you have 11 sats or more and minimum 4 bars for the reception. After takeoff wait and see if HP is set at your current location! For this flight is did not matter if HP was set OK or not. In ATTI the RTH procedure does not work ; just because it does not use GPS signals so Spark doesn`t know where its flying and where HP is located.

cheers
JJB

Nilesh-spark Posted at 2018-7-1 08:29
Hi, thank you for your help. There was no issue with the app. The app stayed on for the duration of the flight, even after it lost control. I did try to push the auto landing button, but it was too late. It was out of sight fairly quickly.  

I hunted again today, and still, could not find it. Had to return home from holiday. It's gone!!!!

Hi Nilesh,

Thanks for your answer. You did try to push the autoland button, mayby that`s why your Spark did autoland in ATTI. The flightrecord shows indeed no connection loss, as you said.

cheers
JJB

JJBspark Posted at 2018-7-1 08:05
Hi mirek,

I never saw a flightrecord where its started an autolanding in ATTI while not disconnected.

JJB,

Yes - This is a great example of HP set while already in flight. Exactly in line with your findings and experiments from other threads where we exchanged these type of questions.

Yes - I have never seen Spark throwing auto-land during ATTI while still connected to the RC.

However, and here is my speculation based on my telecom knowledge but not on how it actually works in Spark:

You have two way communication - up-link (RC to Spark) which allows Spark to receive commands from RC, and down-link (Spark to RC) with information Spark sends and which appears in logs. These links may not be the same strength (transmitters and receivers oin RC and Spark may not be exactly the same plus up down interference may differ slightly).

It is quite possible that, in this case, up-link communication was broken few seconds before down-link.
I could clearly see how NIlesh pushes throttle up in ATTI and Spark responds correctly. However, as of 1m 4 s there is no further input from sticks. Either Nilesh gave up or up-link was broken. We still have down-link for another several seconds and than it also gets broken.

Again - this is speculation because I do not know details of Spark design. But this is consistent with how other communication systems work. I cannot comment on absence of "Signal lost" message. But as we know from experience, messages generated by DJI GO are sometimes inconsistent and out of sync with real events.

Mirek6 Posted at 2018-7-1 10:07
JJB,

Yes - This is a great example of HP set while already in flight. Exactly in line with your findings and experiments from other threads where we exchanged these type of questions.

Hi Mirek,

I understand what you are saying, could be the case.

There is a difference in autoland initiate by the user or by the app. See if i can find this in this flightlog.

cheers
JJB

Nilesh-spark Posted at 2018-7-1 08:47
Hi,

Thanks for your help.  I did not calibrate the IMU or compass before I took off.  However, there was no concrete where I took off from. I took off from paving.  It was in a forest, and there wasn't much electromagnetic interference that I could tell. Did not notice any cell towers.

NIlesh:

You say"I did not calibrate the IMU or compass before I took off.  However, there was no concrete where I took off from. I took off from paving.  It was in a forest, and there wasn't much electromagnetic interference that I could tell. Did not notice any cell towers".

1. When was the last time when you calibrated compass and IMU?
2. How far did you travel to this point from the point of last calibration?
If it was far away from the point of last calibration, 3-dimensional properties of Geo-magnetic field may have been significantly different throwing your magnetometer readings off without calibration.

Lack of magnetic or electromagnetic interference is not enough. If under the pavement you had steel reanforcements or if it was concrete - it may have affected your compass without you even knowing it. This is called hard and/or soft iron effect on magnetometers.

Nevertheless. What you describe is not consistent with normal Spark behavior.
Please respond to my two questions re calibration so we can learn and please open warranty claim ticket with DJI. You have a good chance of being successful with such claim.

Also, If successful - please let us know - it will help others in similar situations.