Downlink Restored messages in flightlogs

[DaleMLind]

Hi, I'm new to the forum and new to the P3SE community. I have experienced on two occasions a situation where the AC went into an auto land mode. The first situation was no problem as it just landed about 6' from me. The second could've been worse. It autolanded on the roof of my house after a relatively simple flight. Batteries were not close to being depleted. The RTH function was NOT initiated by me or automatically. It just started to land and I could not stop it.

I'm on an iPhone7 and running the DJI app.

In both situations, the AC stopped responding to the RC. At the time I still have video. I pulled the .dat files of the roof landing flight and noticed 'downlink restored' after about 17 seconds. This was the last one before the autoland message appeared in the log. The logs also indicated the satellite GPS of about 12-14 the entire time and maybe even a higher number.

Based on my proximity to the roof I suppose the eaves could be blocking the signal. What puzzles me is in other flightlogs that were out in the clear in front of me I noticed the same downlink restored messages and makes me concerned. I would not have known this was even going on. At the time of the event, I noticed the rear LEDs blinking yellow I think, maybe white.

1 - Is the small whip antenna just for wifi between the controller and the mobile device? (I know there are internal antennas as indicated by the 'don't block' message on the RC.)
2 - Is this an indication of a technical problem with the AC/RC considering I have flown in the open and still get the messages?
3 - Could my home wifi network that operations on 2.4/5G impact the communication between the RC and the AC that would cause the auto-land? The home wifi is in the proximity of the house that the AC landed.
4 - any other ideas?

Thanks for the feedback.

Dale

 

[Meta4]

Hi, I'm new to the forum and new to the P3SE community. I have experienced on two occasions a situation where the AC went into an auto land mode. The first situation was no problem as it just landed about 6' from me. The second could've been worse. It autolanded on the roof of my house after a relatively simple flight. Batteries were not close to being depleted. The RTH function was NOT initiated by me or automatically. It just started to land and I could not stop it.

The flight logs may help identify the cause of the autolandings.
Normally the Phantom won't autoland unless it is in a low battery situation but if you have changed your settings for RC Signal Lost, one of the options is Autoland.
The default option is Return to Home and this is more appropriate for most users in most situations.

Downlink Restored refers to the downlink signal - the signal from the Phantom back to your controller, carrying the video and telemetry.
It is normal to lose that before you lose Control Signal (from the controller to Phantom).

1 - Is the small whip antenna just for wifi between the controller and the mobile device? (I know there are internal antennas as indicated by the 'don't block' message on the RC.)
2 - Is this an indication of a technical problem with the AC/RC considering I have flown in the open and still get the messages?
3 - Could my home wifi network that operations on 2.4/5G impact the communication between the RC and the AC that would cause the auto-land? The home wifi is in the proximity of the house that the AC landed.
4 - any other ideas?

1. The antenna is the link between the controller and the Phantom.
It carries the control signal and the downlink and the long side should be facing toward the Phantom.
3. Home wifi and lots of other electrical and radio sources in an urban area all contribute to interference.

 

[DaleMLind]

Thanks for the reply.

The flight logs may help identify the cause of the autolandings.
Normally the Phantom won't autoland unless it is in a low battery situation but if you have changed your settings for RC Signal Lost, one of the options is Autoland.

I pulled the flightlogs (the .txt files assuming), and battery levels were at 65% so that appears out of the equation. I know it's not pretty but there's a paste from the event just prior to the auto-landing kicked in and the downlink restore where the auto kicked in.

7m 3.2s P-GPS 17satellites 51.2ft 3.0mph 39.7ft 65% 15.151V 3.781V 3.793V 3.794V 3.783V 0.013V

7m 21s Auto Landing 16satellites 39.0ft 0.0mph 40.1ft 65% 15.151V 3.781V 3.793V 3.794V 3.783V 0.013V Downlink Restored (after 0m 17.2s)


I have not changed the return to home settings but anything is possible because I may have accidentally hit it. I'll confirm that.

 

[sar104]

If you want a proper assessment of the problem you will need to post the aircraft DAT files that log the unusual behavior. Snippets of the txt file log are not going to tell us anything useful.

 

[DaleMLind]

If you want a proper assessment of the problem you will need to post the aircraft DAT files that log the unusual behavior. Snippets of the txt file log are not going to tell us anything useful.

Fair statement. I have uploaded the txt of that specific flight. By DAT files, are they not the files located in the DJI flightlog files that are on the iPhone? Are there files located in the AC itself that I should access?

 

[BudWalker]

Fair statement. I have uploaded the txt of that specific flight. By DAT files, are they not the files located in the DJI flightlog files that are on the iPhone? Are there files located in the AC itself that I should access?

There are .DAT files on the iPhone but they don't have as much data as the .DAT on the AC itself. Look here

How to retrieve a .DAT

for info about retrieving the .DAT from the P3

 

[DaleMLind]

Thank you. I figured out how to find the files on the AC, pulling them off now.

 

[DaleMLind]

I found the file that contains the auto-land which I have uploaded. I reviewed the file and can't find anything outstanding. Granted, I'm not a pro at reading the data, but the obvious things like battery levels, (within .002v the entire time) and #satellites, etc I can't tell what went on. The compass signal remained consistent throughout. You can see at the very end of the flight where the RC status went disconnected. I can't tell what fields I should add to see what other outside things could influence it to just auto-land.

Question, if it gets into this auto-land state, can you change the mode to ATTI and manually fly out of the auto-land condition?

 

[BudWalker]

I found the file that contains the auto-land which I have uploaded. I reviewed the file and can't find anything outstanding. Granted, I'm not a pro at reading the data, but the obvious things like battery levels, (within .002v the entire time) and #satellites, etc I can't tell what went on. The compass signal remained consistent throughout. You can see at the very end of the flight where the RC status went disconnected. I can't tell what fields I should add to see what other outside things could influence it to just auto-land.

Question, if it gets into this auto-land state, can you change the mode to ATTI and manually fly out of the auto-land condition?

FLY106.DAT isn't the right .DAT. There is no motorStart. Maybe this was the .DAT that was created when you retrieved the .DAT you looked at. The .txt you submitted was 440 secs which would make the corresponding .DAT be at least 84 MB. That's too large to attach here so you'll need to Dropbox or GoogleDrive it and provide a link.

 

[DaleMLind]

Maybe this was the .DAT that was created when you retrieved the .DAT you looked at.

Could you explain that statement? I understand what you mean about the motor start comment.

 

[BudWalker]

Could you explain that statement? I understand what you mean about the motor start comment.

A .DAT is created every time the battery is turned on, even if there isn't a flight. So, a .new DAT was created when you turned on the battery to retrieve the .DAT that you wanted. All I was saying is that maybe you retrieved the new .DAT instead of the one you wanted.

From your description it seemed like you had already reviewed the .DAT. E.g. you referred to the autoLand and compass data. I was a bit puzzled why you didn't submit that .DAT.

 

[DaleMLind]

Oh ok. No, I'm not 100% sure what I'm looking at to be honest. I looked for what appeared to be a disconnect from the radio's point of view which I did see in the .DAT that I tried to upload. It showed the compass signal pretty consistent up to the end of that flight. At the end of FLY106.DAT the radio shows disconnected. The compass didn't change and the auto-land didn't indicate in the file. I'll look around more.

 

[sar104]

Oh ok. No, I'm not 100% sure what I'm looking at to be honest. I looked for what appeared to be a disconnect from the radio's point of view which I did see in the .DAT that I tried to upload. It showed the compass signal pretty consistent up to the end of that flight. At the end of FLY106.DAT the radio shows disconnected. The compass didn't change and the auto-land didn't indicate in the file. I'll look around more.

What you are seeing at the end of that log is just the disconnect on power off. The log does not describe an actual flight - just a 60 second power up at 5:53 pm (EST) on 11/25. The motors were not started and the aircraft did not move. You need to look for an older, and much larger DAT file for the actual flight, as @BudWalker described.

 

[BudWalker]

Oh ok. No, I'm not 100% sure what I'm looking at to be honest. I looked for what appeared to be a disconnect from the radio's point of view which I did see in the .DAT that I tried to upload. It showed the compass signal pretty consistent up to the end of that flight. At the end of FLY106.DAT the radio shows disconnected. The compass didn't change and the auto-land didn't indicate in the file. I'll look around more.

There are some hints about picking the right .DAT here

 

[DaleMLind]

Still learning I do not see where I can tell when the motors start. Any of the Signal motor speed fields report in the log area as empty, not plotting. Flycommand "other" all the time and flightAction none.

 

[sar104]

Still learning I do not see where I can tell when the motors start. Any of the Signal motor speed fields report in the log area as empty, not plotting. Flycommand "other" all the time and flightAction none.

Assuming that you are processing the DAT files using DatCon, you can tell directly from the UI whether a file shows a flight even before processing it. Notice in the screenshot below from your FLY106 file that "Motor Start" and "Motor Stop" are greyed out, i.e. the motors did not start.

 

[BudWalker]

Still learning I do not see where I can tell when the motors start. Any of the Signal motor speed fields report in the log area as empty, not plotting. Flycommand "other" all the time and flightAction none.

Sorry, my mistake. Since this is a P3S the .DAT won't have motor speeds, it only has motor commanded. And, since this is actually a P3SE DatCon (and CsvView) doesn't know where the motor commanded data is. That will be fixed in the next release. For now just look at relativeHeight or flightTime to see if there was actually a flight. Also if there is a flight the trajectory can be seen using the GeoPlayer. Take a look at the info here. for help picking the right .DAT.

 

[DaleMLind]

I still haven't found "the file" that has any real indicators of what happened. I'm sure it's due to the fact that I'm just green at reading the files. I'll keep looking.

Can the files be deleted from the AC? That would give me another way to baseline things if another issue should occur.

I looked at the Flying Flowchart and it says that if a failsafe issue occurs (GPS Satellite number<6) it's supposed to keep leveling and land. That's what mine did. But it also says that when you switch to ATTI mode you can regain control and override the failsafe mode. Has anyone experienced that firsthand? I'm not sure how to even test that other than remember to throw the switch if it actually happens.

 

[BudWalker]

I still haven't found "the file" that has any real indicators of what happened. I'm sure it's due to the fact that I'm just green at reading the files. I'll keep looking.

Can the files be deleted from the AC? That would give me another way to baseline things if another issue should occur.

I looked at the Flying Flowchart and it says that if a failsafe issue occurs (GPS Satellite number<6) it's supposed to keep leveling and land. That's what mine did. But it also says that when you switch to ATTI mode you can regain control and override the failsafe mode. Has anyone experienced that firsthand? I'm not sure how to even test that other than remember to throw the switch if it actually happens.

The .txt you submitted was for a flight that occurred at 2017/11/24 20:46:58.179 GMT. At little more than 1 day later FLY106.DAT was created at time 2017-11-25 21:53:34 GMT. I suspect the .DAT we want is probably in the range FLY102 to FLY105. Why don't you retrieve those and provide them via Dropbox. Judging by the .txt file the .DAT we want is at least 84 MB. It can't be attached to a post, you'll need to Dropbox it.

The .DAT files on the AC can not be deleted.