Another question for the DJI Family. I was flying in sports mdoe, took it over some hills and then over the ocean, shots looked great. I then lost signal and everything cut out, which is normal. I was in S mode not P mode. So it didnt begin to fly back to me towards the Home point till signal regained. Instead it hovered over the ocean. I had to try and get as close as I could to the drone on the shore till thankfull signal returned.   Other models like inspire 1 have been able to come home with no sensors at all. So in sports mode, when sensors are de activated is there a way it can return home? I always have the altitute point set high. Keen to hear peoples thoughts on this as it could be quite scary and disastrious losing signal, in sports mode over areas you cant get to, to get the signal back.

You got lucky, son...


Real good swimmer are ya? Haha

Do those tests over land.  Chuckles


RedHotPoker

The simple answer would have been to shut off the RC unit. It will see that as a definite loss of signal and come home. Unless you had set up the aircraft to hover on loss of signal, it would have only been a short duration loss of signal, so it was actually hovering waiting for you to fly it again. And yes, it can return home wiithout any sensors as long as it has a GPS signal.

Geebax Posted at 2018-7-29 17:03
The simple answer would have been to shut off the RC unit. It will see that as a definite loss of signal and come home. Unless you had set up the aircraft to hover on loss of signal, it would have only been a short duration loss of signal, so it was actually hovering waiting for you to fly it again. And yes, it can return home wiithout any sensors as long as it has a GPS signal.

I'll have to check the settings and see what I have.  One time it lost signal before on another shoot and being in P mode it came back, gained signal then I took over. This time just hovered the whole time.
So turning off the RC, shutting off all the signal it would come home? Yep I always make sure I fly with GPS signal. Thanks for that though, Im going to give it a safe test where I turn off the controller and its right near the home point and see what it does.

Anthony90 Posted at 2018-7-29 19:18
I'll have to check the settings and see what I have.  One time it lost signal before on another shoot and being in P mode it came back, gained signal then I took over. This time just hovered the whole time.
So turning off the RC, shutting off all the signal it would come home? Yep I always make sure I fly with GPS signal. Thanks for that though, Im going to give it a safe test where I turn off the controller and its right near the home point and see what it does.

Good idea, but don't do it close to the controller. If the aircraft loses signal and goes into RTH within 20 Metres of the home point, it will not come home, but land where it is.

Geebax Posted at 2018-7-29 19:44
Good idea, but don't do it close to the controller. If the aircraft loses signal and goes into RTH within 20 Metres of the home point, it will not come home, but land where it is.

Ah okay, too easy, thanks! I'll  make sure its more than 20m away!

RedHotPoker Posted at 2018-7-29 16:55
You got lucky, son...

You're quite the comedian Refreshing to have in these forums haha

I was in S mode not P mode. So it didnt begin to fly back to me towards the Home point till signal regained.
Instead it hovered over the ocean. I had to try and get as close as I could to the drone on the shore till signal returned.   

Other models like inspire 1 have been able to come home with no sensors at all. So in sports mode, when sensors are de activated is there a way it can return home?

This is a muddled misunderstanding of how failsafe RTH works.
Your Phantom works just as any other DJI drone and will return when it loses the control signal.
Flying in Sport mode makes no difference (why would it?)

It sounds like yours just lost the downlink (video and telemetry) but not the control signal.
If that's the case, you should have been able to manually bring the Phantom back or initiate RTH.
Your Phantom was just hovering waiting for you to do something.

The recorded flight data will probably confirm exactly what happened.
To check that, go to http://www.phantomhelp.com/LogViewer/Upload/
Follow the instructions there to upload your flight record from your phone or tablet.
Come back and post a link to the report it gives you.

Labroides Posted at 2018-7-29 20:13
I was in S mode not P mode. So it didnt begin to fly back to me towards the Home point till signal regained.
Instead it hovered over the ocean. I had to try and get as close as I could to the drone on the shore till signal returned.   

All I get is this, the moving/loading cog for ages, when trying to export my flight data from the Phantom..

Anthony90 Posted at 2018-7-29 19:55
You're quite the comedian  Refreshing to have in these forums haha

Yes, laughter is the best medicine.

You should laugh only before or after swimming... hehe


RedHotPoker

Anthony90 Posted at 2018-7-29 20:50
All I get is this, the moving/loading cog for ages, when trying to export my flight data from the Phantom.. [view_image]

The instructions are to upload data from your phone or tablet, not the Phantom.
The app saves a .txt file and that's what you upload to Phantomhelp.
It gives you a detailed report and you come back here and post a link to that report.

Labroides Posted at 2018-7-29 22:49
The instructions are to upload data from your phone or tablet, not the Phantom.
The app saves a .txt file and that's what you upload to Phantomhelp.
It gives you a detailed report and you come back here and post a link to that report.

Im not using the App since I have the inbuilt screen on the controller, have had no luck connecting the drone or controller to my computer and DJI support have not been very helpful assisting me.
I can view the data on the controller but have no way of getting this or the .txt file to a computer at the moment.

Anthony90 Posted at 2018-7-29 23:00
Im not using the App since I have the inbuilt screen on the controller, have had no luck connecting the drone or controller to my computer and DJI support have not been very helpful assisting me.
I can view the data on the controller but have no way of getting this or the .txt file to a computer at the moment.

Your issue is almost certain to be as I explained in post #8.
I've seen many similar cases and they all turned out the same.
I only suggested looking at the data to confirm this.

I haven't got a + model so I've never had to get data from one.
But many other users have done it by following the instructions: https://phantompilots.com/thread ... ur-computer.115600/

Labroides Posted at 2018-7-29 20:13
I was in S mode not P mode. So it didnt begin to fly back to me towards the Home point till signal regained.
Instead it hovered over the ocean. I had to try and get as close as I could to the drone on the shore till signal returned.   

Hey there, got it all sorted. Here is the data from the flight: http://www.phantomhelp.com/LogViewer/QD4CN6CYLPY2MWXP7LLG/#

Labroides Posted at 2018-7-29 23:24
Your issue is almost certain to be as I explained in post #8.
I've seen many similar cases and they all turned out the same.
I only suggested looking at the data to confirm this.

Just uploaded my data if you were curious and wanted to have a look

Labroides Posted at 2018-7-29 23:49
We're getting closer ... that's all good except it's an 8 minute flight where there's no lost signal.
The Phantom is connected for every second of the flight.

Wow okay, so although my RC lost signal, (went black and white etc with red messages no signal, signal lost) I still had control of the drone? sorry for maybe embarrassing my self with this flight earlier today and all the questions. So I could have still flown it although I lost signal, it was just video feed/picture signal lost?

Anthony90 Posted at 2018-7-29 23:32
Hey there, got it all sorted. Here is the data from the flight: http://www.phantomhelp.com/LogViewer/QD4CN6CYLPY2MWXP7LLG/#

At 4:23.8 there's a message saying:
Downlink restored after 15.4 seconds
That's as I expected - you lost downlink (but not the control signal)
You still had full control for the 15 second gap with no video link.

Right wow okay, it was black and white and said no signal for longer than that, or maybe I am mistake in the confusion at the time. So I still had full control, If I had just opened up the GPS map on the bottom left hand corner I would have seen the drone moving to my controls? Damn it. Are there scenarios where you can lose complete control? Is that when it automatically does RTH? Which has happened to me before once. Then once it gets back to signal I have control again.

Anthony90 Posted at 2018-7-29 23:57
Right wow okay, it was black and white and said no signal for longer than that, or maybe I am mistake in the confusion at the time. So I still had full control, If I had just opened up the GPS map on the bottom left hand corner I would have seen the drone moving to my controls? Damn it. Are there scenarios where you can lose complete control? Is that when it automatically does RTH? Which has happened to me before once. Then once it gets back to signal I have control again.

Sometimes you lose connection completely but it's also  common to lose downlink before losing control signal.
If you think you might have lost signal, check the coloured LED on the controller.
Green if connected - Red when connection is lost.
If in doubt, shut down the controller for 30 seconds and definitely lose connection to trigger RTH.

Labroides Posted at 2018-7-29 23:55
At 4:23.8 there's a message saying:
Downlink restored after 15.4 seconds
That's as I expected - you lost downlink (but not the control signal)

I'm not convinced that is correct, I take "lost downlink" to mean loss of control, not just video, but 15 seconds is not enough time for it to be flying back home, it had only got as far as rotating to retrace the last part of it's route looking to regain the control signal having moved out of the way of any obstacle that had blocked the signal, which since it wasn't moving when it lost connection didn't take it very far.

A proper flight back towards home doesn't begin until 30 seconds after loss of connection, so basically it was still waiting for the ship that had blocked the signal path to move out of the way before attempting to flying directly home through that ship.


It is good to test these things so that you know how they work, and that they do work.

Labroides Posted at 2018-7-30 00:12
Sometimes you lose connection completely but it's also  common to lose downlink before losing control signal.
If you think you might have lost signal, check the coloured LED on the controller.
Green if connected - Red when connection is lost.

Got it! So RED light would mean connection lost and RTH activates. Green light but no pictures means I can still fly. Great!  So either way I won't get stuck and my drone is at risk.

Nigel_ Posted at 2018-7-30 00:18
I'm not convinced that is correct, I take "lost downlink" to mean loss of control, not just video, but 15 seconds is not enough time for it to be flying back home, it had only got as far as rotating to retrace the last part of it's route looking to regain the control signal having moved out of the way of any obstacle that had blocked the signal, which since it wasn't moving when it lost connection didn't take it very far.

A proper flight back towards home doesn't begin until 30 seconds after loss of connection, so basically it was still waiting for the ship that had blocked the signal path to move out of the way before attempting to flying directly home through that ship.

I'm not convinced that is correct, I take "lost downlink" to mean loss of control, not just video
You might not be convinced but you'd be wrong.
Downlink means the video + telemetry signal that travels down from the Phantom to the controller.
This can be confirmed by looking at the recorded data from the many, many cases where the Phantom loses just the video+telemetry link.

It is different from the control signal or upling which travels up to the Phantom.

but 15 seconds is not enough time for it to be flying back home, it had only got as far as rotating to retrace the last part of it's route looking to regain the control signal

While the Phantom has rotated from facing 72.8° to facing 175° during the missing 15 seconds, this is accounted for by looking at the joystick movement at the time downlink was lost.
The left stick was pushed to one side - that rotated the Phantom

A proper flight back towards home doesn't begin until 30 seconds after loss of connection
Correction ... after 3 seconds of lost connection, the Phantom commences RTH.
Failsafe  RTH  will  be  automatically  activated  if  the  remote  controller  signal  is  lost  for  more  than  three  seconds.  (p15 of the P4 pro manual)

so basically it was still waiting for the ship that had blocked the signal path to move out of the way before attempting to flying directly home through that ship.
Ship?  What ship?
The Phantom was launched from a point about 10 ft above sea level.
At the time it lost downlink, the Phantom was approx 126 feet higher then the launch point and 30-40 feet offshore in the surfbreak zone.
There's no way any ship was blocking signal.
What interfered with the signal was the vegetation on top of a small (80 ft) hill 700 feet NE of the home point.

But having no Picture on the screen you must be aware that you don't see where you flying. You'll see only the way which you are flying to.
If you are not sure about obstackles, go high  to be 100% sure that you'll be flying above all.
If you have no visual contact of course.
Regards!

andy10 Posted at 2018-7-30 01:58
But having no Picture on the screen you must be aware that you don't see where you flying. You'll see only the way which you are flying to.
If you are not sure about obstackles, go high  to be 100% sure that you'll be flying above all.
Regards!

Oh yes without doubt, however I could open the map and see where I am flying and what direction. I always make sure I am high if there is any doubt and RTH is set at least 100m.

Anthony90 Posted at 2018-7-30 02:01
Oh yes without doubt, however I could open the map and see where I am flying and what direction. I always make sure I am high if there is any doubt and RTH is set at least 100m.

Although you could open the map, without any data coming back from the aircraft, it is not possible for the map display to be correct.  You can loose video without loosing data, but in this case you had 15 seconds without the data downlink.

When you said "I had to try and get as close as I could to the drone on the shore...", you only walked 5m before you got the downlink back, I guess after that the map was correct but you still had no video since you continued to 20m distance.

RedHotPoker Posted at 2018-7-29 20:51
Yes, laughter is the best medicine.

You should laugh only before or after swimming... hehe

Very good advice indeed !

True!!

Sorry, I must have fallen asleep, and got back to this much later...

RedHotPoker

I would like to remind everyone that the flight log obtained from within DJIGo4 (whether decoded within the app or its extended version obtained via phantomhelp) can only give information about events that occurred while the video downlink was present. If that downlink is interrupted no information about the state of the AC can be obtained or recovered. It cannot be determined if the control is lost or not or intermittent. The only indication for existing control is the green indicator on the RC.
What happened during loss of video downlink is subject to conjecture and only data retrieved from the AC after the flight (like video recording on the onboard memory) can give valid info. Needed would be to access the flight data stored within the AC (not DJIGo4).
Does anyone know how to retrieve flight data from the drone itself and how to decode it?

oldhasbeen Posted at 2018-7-31 14:16
I would like to remind everyone that the flight log obtained from within DJIGo4 (whether decoded within the app or its extended version obtained via phantomhelp) can only give information about events that occurred while the video downlink was present. If that downlink is interrupted no information about the state of the AC can be obtained or recovered. It cannot be determined if the control is lost or not or intermittent. The only indication for existing control is the green indicator on the RC.
What happened during loss of video downlink is subject to conjecture and only data retrieved from the AC after the flight (like video recording on the onboard memory) can give valid info. Needed would be to access the flight data stored within the AC (not DJIGo4).
Does anyone know how to retrieve flight data from the drone itself and how to decode it?

There is a lot of validity to what you're saying, but I think it's a little more than conjecture when we try to figure out what happened after the loss of the downlink.  If the downlink is lost, and the AC does not come home when we know it is programmed to come home with loss of the control signal, then there are only three explanations - there actually is not a loss of a good control signal, or there was a loss of satellites, or the AC just dropped out of the sky.  And since we know a drop out of the sky is highly unlikely, and since we know loss of satellites is highly unlikely, and since we know loss of downlink always occurs before loss of control, we can surmise what happened.  

Geebax Posted at 2018-7-29 19:44
Good idea, but don't do it close to the controller. If the aircraft loses signal and goes into RTH within 20 Metres of the home point, it will not come home, but land where it is.

I don't get that?  Why would DJI make the drone land under 20 meters?

Christine96 Posted at 2018-7-31 16:24
I don't get that?  Why would DJI make the drone land under 20 meters?

We've been debating that for quite a few years.  

My take is that DJI doesn't see any sense in having to rise up to the min RTH height to RTH horizontally only 20 meters.  Especially since it's highly likely the pilot is standing right there.  So it just lands. If there's a problem with the landing spot, the pilot can cancel RTH and safely land it.  

Others have other theories.  

Mark The Droner Posted at 2018-7-31 16:44
We've been debating that for quite a few years.  

My take is that DJI doesn't see any sense in having to rise up to the min RTH height to RTH horizontally only 20 meters.  Especially since it's highly likely the pilot is standing right there.  So it just lands. If there's a problem with the landing spot, the pilot can cancel RTH and safely land it.  

I tried a test today and was a bit concerned. I have RTH on, all the settings on, and where it says loss of signal = hover OR RTH I have RTH on.  I turned off the controller to test a loss of complete signal, which another user recommended I do. So on a football oval with full control over the situation I turned off the RC. The drone just hovered there, it didn't do anything. No RTH? Why is this. 1 time it RTH on its own after a loss of signal, then this last time over the water it didn't. Then during this test it just hovered too..

Geebax Posted at 2018-7-29 19:44
Good idea, but don't do it close to the controller. If the aircraft loses signal and goes into RTH within 20 Metres of the home point, it will not come home, but land where it is.

I tested this today, it just hovered. Although I have triple checked my settings it just hovered and did not RTH. Why doesn't the settings I have chosen transfer and correspond? I don't want it to just hover when RC signal is lost I want it to begin to return to home and into signal.   

Manxmann Posted at 2018-7-31 01:02
Very good advice indeed !

Haha agreed

oldhasbeen Posted at 2018-7-31 14:16
I would like to remind everyone that the flight log obtained from within DJIGo4 (whether decoded within the app or its extended version obtained via phantomhelp) can only give information about events that occurred while the video downlink was present. If that downlink is interrupted no information about the state of the AC can be obtained or recovered. It cannot be determined if the control is lost or not or intermittent. The only indication for existing control is the green indicator on the RC.
What happened during loss of video downlink is subject to conjecture and only data retrieved from the AC after the flight (like video recording on the onboard memory) can give valid info. Needed would be to access the flight data stored within the AC (not DJIGo4).
Does anyone know how to retrieve flight data from the drone itself and how to decode it?

Id love to know also. Every time I plug the drone into a computer through DJI Assistant it never comes up with data.

Anthony90 Posted at 2018-7-31 21:26
I tested this today, it just hovered. Although I have triple checked my settings it just hovered and did not RTH. Why doesn't the settings I have chosen transfer and correspond? I don't want it to just hover when RC signal is lost I want it to begin to return to home and into signal.   [view_image]

Why doesn't the settings I have chosen transfer and correspond? I don't want it to just hover when RC signal is lost I want it to begin to return to home and into signal.  
The first thing I'd ask is:  How long did you give it to start RTH?
The + model takes a little longer to stop transmitting after you shut down the controller.

Labroides Posted at 2018-7-31 21:47
Why doesn't the settings I have chosen transfer and correspond? I don't want it to just hover when RC signal is lost I want it to begin to return to home and into signal.  
The first thing I'd ask is:  How long did you give it to start RTH?
The + model takes a little longer to stop transmitting after you shut down the controller.

I waited about 15-30 seconds. Then powered on the controller again. Should I try and wait longer next time?

Anthony90 Posted at 2018-7-31 21:57
I waited about 15-30 seconds. Then powered on the controller again. Should I try and wait longer next time?

Yes ... it still transmits for a bit after you switch off.
Watch the coloured LED while you do it.

Labroides Posted at 2018-7-31 22:33
Yes ... it still transmits for a bit after you switch off.
Watch the coloured LED while you do it.

No problems, Ill wait a bit longer next time I give it a test. Sadly I flew for 25 minutes, then before landing did the test, so I lost all my flight records on the controller and couldn't sync it to my account for the flight distance, time, etc etc. Silly me.

Anthony90 Posted at 2018-7-31 22:37
No problems, Ill wait a bit longer next time I give it a test. Sadly I flew for 25 minutes, then before landing did the test, so I lost all my flight records on the controller and couldn't sync it to my account for the flight distance, time, etc etc. Silly me.

You should not have lots the records, they are not on the controller anyway, they are in the screen device.