Loosing GPS mid flight
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djiuser_DxN9oIxXFlr4
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This has happened to me twice now. Flying along and all of a sudden,gps is gone and I have to immediately land the drone since it's unusable without gps and I don't want to risk losing the link with the remote when rth isn't going to work.

The only thing even remotely unusual was cloud cover. They were fairly thick clouds overhead, but I was not flying in the clouds or even close to them.

Could GPS be affected by bad weather or is something wrong with the drone? The GPS on my phone is working fine.

I landed it asap when I lost gps, turned it off. Waited a minute and restarted it. It got a GPS lock but then lost it again a minute after I took off.
2018-3-14
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Hellsgate
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I believe that in some parts of the states they are turning off and or testing the gps network you may be in one of those locations thats being interrupted by it
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Labroides
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That's not normal.
GPS is unaffected by weather.
Compass issues are the most common cause of "losing GPS", checking your flight records would confirm whether it was a factor in your case.
What part of the US are you flying in?
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Landbo
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The only thing even remotely unusual was cloud cover. They were fairly thick clouds overhead, but I was not flying in the clouds or even close to them.

Yes a thick cloud cover with a lot of moisture (water) in damping the GPS radio signals.

That the drone switching to ATTI mode can also happens due to a badly-calibrated compass. Try a compass callibling on an open field.

Regards Leif.
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StanfordWebbie
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Also, were you flying directly overhead?  I don't know if that causes loss of GPS or just loss of contact with the remote, but if the antennas are pointing straight up at a drone directly overhead, you risk losing signal.
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Geebax
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StanfordWebbie Posted at 2018-3-14 16:01
Also, were you flying directly overhead?  I don't know if that causes loss of GPS or just loss of contact with the remote, but if the antennas are pointing straight up at a drone directly overhead, you risk losing signal.

Flying overhead has nothing to do with GPS, all it does is weaken the radio link between the RC unit and the aircraft.
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djiuser_DxN9oIxXFlr4
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Labroides Posted at 2018-3-14 13:51
That's not normal.
GPS is unaffected by weather.
Compass issues are the most common cause of "losing GPS", checking your flight records would confirm whether it was a factor in your case.

How would i go about checking the flight records to determine what actually happened? I thought they were encrypted and only dji could read them? Never understood that. Oh, and I'm in california - the bay area.
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djiuser_DxN9oIxXFlr4
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Hellsgate Posted at 2018-3-14 13:02
I believe that in some parts of the states they are turning off and or testing the gps network you may be in one of those locations thats being interrupted by it

I just googled it - looks like the airforce was jamming GPS signals in the western US but that should have ended a month ago. Plus i haven't noticed any GPS problems on my phone.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 18:15
I just googled it - looks like the airforce was jamming GPS signals in the western US but that should have ended a month ago. Plus i haven't noticed any GPS problems on my phone.

Was just a thought.
I cant see that cloud cover would block your gps.
Its posible you may have a fault with the drone.
You may wish to contact dji support and start a claim to get the drone looked at.
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Geebax
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 18:11
How would i go about checking the flight records to determine what actually happened? I thought they were encrypted and only dji could read them? Never understood that. Oh, and I'm in california - the bay area.

Go to here: http://www.phantomhelp.com/LogViewer/Upload/
and follow the prompts. Come back here and post a link to the log. That may tell us what happened.

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djiuser_DxN9oIxXFlr4
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Geebax Posted at 2018-3-14 18:32
Go to here: http://www.phantomhelp.com/LogViewer/Upload/
and follow the prompts. Come back here and post a link to the log. That may tell us what happened.

http://www.phantomhelp.com/LogViewer/J7Y0G06MEIRQFQQD0FF4/

obviously i'm a newb at reading this. The only thing i can see is at just before 3 minutes it had 16 satellites, and then suddenly goes to 0, comes back with the satellites a few seconds later and then at around 3m45s they start to drop in and out before finally just dropping out for good.
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djiuser_DxN9oIxXFlr4
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http://www.phantomhelp.com/LogViewer/5S262LAS03VW0AUJM0JA/
This is the 2nd flight, same day a minute or two apart. After i restarted the drone and it got a gps lock i figured it was just a glitch and took off again - 30 seconds in it lost all gps again. Although the odd thing is it shows it picked up the gps again about 45 seconds later. I don't remember it coming out of atti mode. But it was also pretty freaked out since it's not exactly easy flying that thing without gps. I was just focused on getting it down so I might have missed it going back into gps.
I also just noticed on the first one, at the very end it says it's back in gps mode, but it's showing zero satellites still.

One more note - this happened a few days ago as well, on the 9th. Just looked over that log and it also at the very end says p-gps with 0 satellites - seems to happen when the drone under 100 feet. I also noticed when trying to land it that it seemed to get much more stable in terms of holding position when it got it lower to the ground. I just assumed at the time that it was low enough where there was less wind. Is that the vision system kicking in?
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Geebax
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 19:03
http://www.phantomhelp.com/LogViewer/5S262LAS03VW0AUJM0JA/
This is the 2nd flight, same day a minute or two apart. After i restarted the drone and it got a gps lock i figured it was just a glitch and took off again - 30 seconds in it lost all gps again. Although the odd thing is it shows it picked up the gps again about 45 seconds later. I don't remember it coming out of atti mode. But it was also pretty freaked out since it's not exactly easy flying that thing without gps. I was just focused on getting it down so I might have missed it going back into gps.
I also just noticed on the first one, at the very end it says it's back in gps mode, but it's showing zero satellites still.

Have you added or fitted any accessories to the aircraft, specifically anything on the top of the aircraft?
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djiuser_DxN9oIxXFlr4
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Geebax Posted at 2018-3-14 19:47
Have you added or fitted any accessories to the aircraft, specifically anything on the top of the aircraft?

Not at all - everything on there is what came with it.  Not using any sort of 3rd party products or accessories.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 18:11
How would i go about checking the flight records to determine what actually happened? I thought they were encrypted and only dji could read them? Never understood that. Oh, and I'm in california - the bay area.

It probably wasn't the government testing.
Checking flight data is easy.
You can get a basic look at flight records by going to the flight records section of the app (click on Me down in bottom right).
For each record, you can replay and look at some of the data.
For a more detailed look, you go to: http://www.phantomhelp.com/LogViewer/Upload/
... and upload the flight record you are interested in.
That site will give you a detailed report and complete flight data.
We use this extensively when investigating flight incidents.
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Geebax
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 19:59
Not at all - everything on there is what came with it.  Not using any sort of 3rd party products or accessories.

I think you need to send the aircraft to DJI for investigation, it does appear to be losing GPS connection from time to time.
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Bashy
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Tis weird, goes from 12 sats to 0 in just under 1 second, vps alt goes from 51.5ft to n/a too prior to the loss of gps
I do not see anything that would cause this in your neighbourhood, being under those tress would lower the gps, the mountains wont be an issue.

My p4p has issues directly relating to the acquiring gps signals when under trees or surround by them, compared to a mavic, i can be waiting minutes longer before i am safe to fly, this is not really related i dont think but thougth i would menton it seen as you do have trees
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djiuser_DxN9oIxXFlr4
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Bashy Posted at 2018-3-14 21:22
Tis weird, goes from 12 sats to 0 in just under 1 second, vps alt goes from 51.5ft to n/a too prior to the loss of gps
I do not see anything that would cause this in your neighbourhood, being under those tress would lower the gps, the mountains wont be an issue.

Yeah i dont really think it's the trees since this occurred when the phantom was well above and away from any trees. When i get home tomorrow I'm going to test it out - just going to let it hover 300 ft over my house for a while and see if it looses gps again.  I did that once already but i didn't go that high, and there were some birds flying around so i didn't keep it up there very long either.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 21:35
Yeah i dont really think it's the trees since this occurred when the phantom was well above and away from any trees. When i get home tomorrow I'm going to test it out - just going to let it hover 300 ft over my house for a while and see if it looses gps again.  I did that once already but i didn't go that high, and there were some birds flying around so i didn't keep it up there very long either.

Good point,  if i was you, i would calibrate everything again, well, the IMU and the Compass, go find a field and do the compass there, well away from any concrete or metals
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djiuser_DxN9oIxXFlr4
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Bashy Posted at 2018-3-14 21:42
Good point,  if i was you, i would calibrate everything again, well, the IMU and the Compass, go find a field and do the compass there, well away from any concrete or metals

Would the IMU and compass effect the gps though? It says it's actually losing all the gps satellites when it goes to atti mode.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 22:08
Would the IMU and compass effect the gps though? It says it's actually losing all the gps satellites when it goes to atti mode.

No, it won't and that's why I recommend you return it to DJI for repair.
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Just to verify, does the issue remains if changed to another location without interference? If yes, I'm afraid that you have to send it in for diagnosis. Please kindly start a case from here: https://www.dji.com/support
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Labroides
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 18:59
http://www.phantomhelp.com/LogViewer/J7Y0G06MEIRQFQQD0FF4/

obviously i'm a newb at reading this. The only thing i can see is at just before 3 minutes it had 16 satellites, and then suddenly goes to 0, comes back with the satellites a few seconds later and then at around 3m45s they start to drop in and out before finally just dropping out for good.

There is something wrong with that Phantom.
That's not normal at all.

It needs to go back for fixing.
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Labroides
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-14 22:08
Would the IMU and compass effect the gps though? It says it's actually losing all the gps satellites when it goes to atti mode.

Would the IMU and compass effect the gps though?
Not at all - would the car's air conditioning affect the transmission?
They are quite separate systems.
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When did you fly? On the 14th?
I'm not the conspiracy type of guy and don't believe much in Satellite Failures.
But yesterday something really hit the earth:
http://www.dailymail.co.uk/sciencetech/article-5494489/Huge-solar-storm-set-slam-Earth-TOMORROW.html
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djiuser_DxN9oIxXFlr4
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Eric13 Posted at 2018-3-15 03:37
When did you fly? On the 14th?
I'm not the conspiracy type of guy and don't believe much in Satellite Failures.
But yesterday something really hit the earth:

Yes i did. I flew it at my house today and I'm not sure - it lost gps for a half second and then got it back. Had it flying around for 5 minutes or so and it was fine. I was a little worried about keeping it up too long since the winds were pretty strong at my house today. I'm going back out to the same location tomorrow where i lost the gps and I'll see what happens. Hopefully that flare was the cause
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Eric13 Posted at 2018-3-15 03:37
When did you fly? On the 14th?
I'm not the conspiracy type of guy and don't believe much in Satellite Failures.
But yesterday something really hit the earth:

Those sky-is-falling stories pop up every few months but so far, none of their dire predictions have occurred.
Phantoms haven't been affected at all.
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djiuser_DxN9oIxXFlr4
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Labroides Posted at 2018-3-15 22:35
Those sky-is-falling stories pop up every few months but so far, none of their dire predictions have occurred.
Phantoms haven't been affected at all.

Well - i was back at the same location today and didn't have any issues with the gps. It was cloudy, although slightly less cloudy then last time. And I also tried to keep it below 200 ft seem it also seemed to only happen when I was above 200 ft. Could also just be a coincidence of timing since i usually take the lower shots first and then go higher.

Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.
2018-3-16
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-16 16:09
Well - i was back at the same location today and didn't have any issues with the gps. It was cloudy, although slightly less cloudy then last time. And I also tried to keep it below 200 ft seem it also seemed to only happen when I was above 200 ft. Could also just be a coincidence of timing since i usually take the lower shots first and then go higher.

Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.

Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.
It had nothing to do with solar activity and was unrelated to your Phantom's altitude or clouds.
Any impact on GPS dur to soalr activity would have been a minor variation in the accuracy of the GPS position.
And it would have been so small that you'd never notice.
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djiuser_DxN9oIxXFlr4
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Labroides Posted at 2018-3-16 16:40
Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.
It had nothing to do with solar activity and was unrelated to your Phantom's altitude or clouds.
Any impact on GPS dur to soalr activity would have been a minor variation in the accuracy of the GPS position.

Could have been related to altitude, if there was some sort of interference only above a certain altitude, no?
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-16 16:42
Could have been related to altitude, if there was some sort of interference only above a certain altitude, no?

No ... that's not how GPS works.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-16 16:09
Well - i was back at the same location today and didn't have any issues with the gps. It was cloudy, although slightly less cloudy then last time. And I also tried to keep it below 200 ft seem it also seemed to only happen when I was above 200 ft. Could also just be a coincidence of timing since i usually take the lower shots first and then go higher.

Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.

'Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.'

The GPS receiver in the Phantom is several orders better than any receiver fitted to a phone, both in its ability to receive weak signals and also its accuracy.
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djiuser_DxN9oIxXFlr4
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Geebax Posted at 2018-3-16 17:28
'Perhaps the solar flare did have something to do with it - maybe the gps receiver in the phantom is not as good as the one in my phone, since my phone never lost gps that i noticed.'

The GPS receiver in the Phantom is several orders better than any receiver fitted to a phone, both in its ability to receive weak signals and also its accuracy.

well then I don't really have any more ideas as to what happened, unless there is something wrong with the gps receiver but whatever it is is intermittent.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-16 18:20
well then I don't really have any more ideas as to what happened, unless there is something wrong with the gps receiver but whatever it is is intermittent.

Refer my post #16
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djiuser_DxN9oIxXFlr4
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Happened again today for just a second - totally different location. GPS signal came back almost instantly. The only thing unusual i can think of is that I was flying very close to some power lines. Although I believe the lines were below me, so not sure if that would cause any issues.

Maybe when i get my mavic back (imu failed) i'll send the phantom in to get checked out.
2018-3-23
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Geebax
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-23 15:16
Happened again today for just a second - totally different location. GPS signal came back almost instantly. The only thing unusual i can think of is that I was flying very close to some power lines. Although I believe the lines were below me, so not sure if that would cause any issues.

Maybe when i get my mavic back (imu failed) i'll send the phantom in to get checked out.

Power lines have no effect on a drone, unless you hit them. It does not interfere with GPS reception. The only thing I can think of is that you are in some sort of valley or canyon, limiting the visibility of the sky. If not, then yes, send it in for repair.
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djiuser_DxN9oIxXFlr4
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Geebax Posted at 2018-3-23 15:18
Power lines have no effect on a drone, unless you hit them. It does not interfere with GPS reception. The only thing I can think of is that you are in some sort of valley or canyon, limiting the visibility of the sky. If not, then yes, send it in for repair.

There were a lot of hills, and i was relatively close to the ground, maybe close enough to block a signal if the satellite was very close to the horizon. But I think it had 15 or satellites at the time the signal went out for a second. And i think the horizon might have been blocked only for a small section of the sky.
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djiuser_DxN9oIxXFlr4 Posted at 2018-3-23 15:21
There were a lot of hills, and i was relatively close to the ground, maybe close enough to block a signal if the satellite was very close to the horizon. But I think it had 15 or satellites at the time the signal went out for a second. And i think the horizon might have been blocked only for a small section of the sky.

OK, so it can actually see a good number of satellites, then the only problem is the strength of reception. Do you have anything on the top of your aircraft? Even a sticker?
2018-3-23
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Phantomrain.org 1 Posted at 2018-3-23 20:45
There was a firmware that was a bit older that had these issues,   what firmware are you running now ?         One in particular that would show magnetic resistance before loosing GPS signal and going into  atty mode.   You do not mention atty mode but is that what is happening when you loose gps ?     Are you running an older firmware ?

Are you sure about the firmware explanation?
I've heard a lot of firmware stories but never that one.

He has a bad GPS unit or a bad connection between the GPS and motherboard.
It's not a firmware issue.
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djiuser_DxN9oIxXFlr4
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Phantomrain.org 1 Posted at 2018-3-23 20:45
There was a firmware that was a bit older that had these issues,   what firmware are you running now ?         One in particular that would show magnetic resistance before loosing GPS signal and going into  atty mode.   You do not mention atty mode but is that what is happening when you loose gps ?     Are you running an older firmware ?

Pretty sure it's the latest firmware. I'll double check, but I'm pretty sure I updated it a few weeks ago.

It did go into atti mode - but doesn't it always go into atti mode if there's no gps? And nothing at all on top of the drone - it's exactly as it came out of the box when i first got it.

I really wish i could open it up without voiding the warranty. Seems pretty stupid having to ship it back and forth if it's just a lose connection.
2018-3-23
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