Gps drop

[Anthonyk]

Well after many flights 37+. I experienced my first gps drop. After the mavic switched to atti mode I was able to fly it back no problem. Thank you Syma. Lol after checking things out I saw a IMU error in flight. So just looking things over and checking UAV forecast again. I saw the kp index had went up to 4. Being that I have always errored on the cautious side I never fly when it's over 3. I wonder if this is what may be causing gps loss at times. Being a amateur radio operator I know that atmospheric conditions can cause a lot of issues with radio signals. And being the kp index is a measurement of geomagnetic storms effect on the atmosphere. Could this be part of the cause in drop gps? Just a thought! And I'm thankful I learned to fly without gps assistance. As it kept me from panicking because when the drown first switched it took a few seconds for the drone to respond to stick input. But thank you DJI for this awesome machine.

 

[AlanTheBeast]

Well after many flights 37+. I experienced my first gps drop. After the mavic switched to atti mode I was able to fly it back no problem. Thank you Syma. Lol after checking things out I saw a IMU error in flight. So just looking things over and checking UAV forecast again. I saw the kp index had went up to 4. Being that I have always errored on the cautious side I never fly when it's over 3. I wonder if this is what may be causing gps loss at times. Being a amateur radio operator I know that atmospheric conditions can cause a lot of issues with radio signals. And being the kp index is a measurement of geomagnetic storms effect on the atmosphere. Could this be part of the cause in drop gps? Just a thought! And I'm thankful I learned to fly without gps assistance. As it kept me from panicking because when the drown first switched it took a few seconds for the drone to respond to stick input. But thank you DJI for this awesome machine.

I suspect that because the MP uses an over-sensitive GPS receiver that increased kp may have a greater impact than it should. GPS should not be affected except in extremes of kp, but because the receiver is so sensitive (way beyond need) that the increased noise upsets the receiver - may even make the correlators fail to lock onto some or many sats. (I don't know enough about GLONASS to comment on that but its signal is pretty close in f and obviously needs to traverse the ionosphere too).

That said, in 25+ years involvement with GPS I've never known any to be as finicky as the Mavic GPS. I've had a few drops but of very brief duration (less than 10 s.). Lucky me, I suppose.

A drone flies in fantastically optimal conditions for GPS/GLONASS (and soon Galileo and Beidou) reception - so there is no need for such aggressively sensitive receivers. It's not like it's in the bottom of a purse under the car seat.

And if DJI would grow a pair and integrate the GPS and IMU more tightly, it could navigate accurately enough on IMU alone to get near enough to the home point for the operator to take over. (This for the case where VLOS is lost).

 

[Anthonyk]

After reviewing the flight log for this flight. I saw a week gps alert just before the mavic switched to atti mode. After that is when the imu error popped up.

 

[Wombat55]

And if DJI would grow a pair and integrate the GPS and IMU more tightly, it could navigate accurately enough on IMU alone to get near enough to the home point for the operator to take over. (This for the case where VLOS is lost).

You mean using the accelerometers in an IMU to calculate distances traveled by doing a double integration of the acceleration history to get the distance? If so, doubt that the accelerometers in a Mavic are sensitive enough to do that. I looked into programming something like that using an iPhone's built-in accelerometers and gyros, but after a back-of-the-envelope calculation concluded that the iPhone's accelerometers are not nearly sensitive enough. I think that this approach may be is used with modern US Navy submarines, but if so they probably use much more sensitive and accurate laser accelerometers and laser gyros.

 

[Fletcher500]

[QUOTE That said, in 25+ years involvement with GPS I've never known any to be as finicky as the Mavic GPS. I've had a few drops but of very brief duration (less than 10 s.). Lucky me, I suppose.).[/QUOTE]

Had my first GPS drop last night, and it only lasted a few seconds as well.

I was on a cliff, the Quad was over the ocean, about 1/4 mile away.

 

[mavicpro7337]

I had this problem when I first started flying my Mavic out of the box. I was able to fix it by calibrating the IMU and the compass. Believe it or not the compass is the cause for most GPS signal loss.

 

[Scamp]

I coincidentally had my first gps loss after 60 flights last night. It scared the hell out of me even though it was only 10 seconds or so. I was trying to capture the sunset so light wasn't great and I'm vacationing so I don't know the landmarks really well. Like the OP I had a gps loss followed by an IMU error. I'm not sure if I could still fly the controls or not it was so brief I could change yaw and was trying to get my bearings.

I have a few questions -

1) what is KP and how important is it?

2) if you lose gps and go into Atti mode what can you count on working vs not working? I am assuming you have only what the camera shows you so you must know your landmarks to fly back to yourself. I assume the map and the direction it indicates is no longer valid. Can altitude be trusted?

3) is there a good source of tips on how to respond to a loss of GPS. I'll go searching now but I came straight here since I saw the original post is exactly what I experienced.

Thanks
Scott

FYI I'm on .500 and 4.0.6 if it matters.

 

[rydfree]

I have my UAV forecast app to show red when KP is over 3 also . My drones with Eagle Tree Vector flight controls would lose GPS intermediately and it seemed to correlate with the higher KP days . I still fly but I don't go out as far and stay alert in case the GPS goes out . So far my Mavic hasn't lost GPS .

 

[Anthonyk]

I coincidentally had my first gps loss after 60 flights last night. It scared the **** out of me even though it was only 10 seconds or so. I was trying to capture the sunset so light wasn't great and I'm vacationing so I don't know the landmarks really well. Like the OP I had a gps loss followed by an IMU error. I'm not sure if I could still fly the controls or not it was so brief I could change yaw and was trying to get my bearings.

I have a few questions -

1) what is KP and how important is it?

2) if you lose gps and go into Atti mode what can you count on working vs not working? I am assuming you have only what the camera shows you so you must know your landmarks to fly back to yourself. I assume the map and the direction it indicates is no longer valid. Can altitude be trusted?

3) is there a good source of tips on how to respond to a loss of GPS. I'll go searching now but I came straight here since I saw the original post is exactly what I experienced.

Thanks
Scott

FYI I'm on .500 and 4.0.6 if it matters.

The only advice I can give on a gps drop is DONT PANIC!!! Lol just easy stick movement till you see the drone respond then fly it back to you.

 

[Fletcher500]

The only advice I can give on a gps drop is DONT PANIC!!! Lol just easy stick movement till you see the drone respond then fly it back to you.

New to this game, so correct me if I am wrong, but this statement doesn't make sense.

If you have an extended GPS loss, then both the APP and RC are black. Right?

So how do know if you are closing the distance from home?

And for the people who say you should have a visual, VLOS, happens due to the sun, and other factors.

I am interested to hear responses to Scamp. I think he brings up some good questions.

 

[Wombat55]

The only advice I can give on a gps drop is DONT PANIC!!!

Like how you soothed him from panicking by writing "don't panic" in all caps and adding three exclamation marks to boot.

 

[Anthonyk]

New to this game, so correct me if I am wrong, but this statement doesn't make sense.

If you have an extended GPS loss, then both the APP and RC are black. Right?

So how do know if you are closing the distance from home?

And for the people who say you should have a visual, VLOS, happens due to the sun, and other factors.

I am interested to hear responses to Scamp. I think he brings up some good questions.

No when you have gps drop the remote and app up and running. The controller will give you the gps loss warning. And you should still have video.

 

[Johnmcl7]

New to this game, so correct me if I am wrong, but this statement doesn't make sense.

If you have an extended GPS loss, then both the APP and RC are black. Right?

So how do know if you are closing the distance from home?

And for the people who say you should have a visual, VLOS, happens due to the sun, and other factors.

I am interested to hear responses to Scamp. I think he brings up some good questions.

No, when the Mavic loses GPS it doesn't know where it is which means it can't keep itself as steady so it will likely drift and not respond as well as it does when it has GPS reception. You'll still have the feed from the camera but you'll need to be much more careful with the controls since the drone can't steady itself using GPS data.

John

 

[Scamp]

You guys are hysterical. I WILL TRY NOT TO PANIC!!!

I've been trying to read up on all the posts and it seems like a lot of incidents are related (possibly thru coincidence) with sport mode. Several incidents discuss a switch to sport being a possible trigger of gps loss or Toilet Bowl Effect TBE. At least one person seemed to be able to regain control by switching INTO sport mode.

Since I don't typically use sport mode I wonder if the problem can be eliminated by disabling Multiple Flights Mode.

Can anyone report they have had TBE or gps loss while the Multiple Mode was disabled in the app?

 

[Anthonyk]

I coincidentally had my first gps loss after 60 flights last night. It scared the **** out of me even though it was only 10 seconds or so. I was trying to capture the sunset so light wasn't great and I'm vacationing so I don't know the landmarks really well. Like the OP I had a gps loss followed by an IMU error. I'm not sure if I could still fly the controls or not it was so brief I could change yaw and was trying to get my bearings.

I have a few questions -

1) what is KP and how important is it?

2) if you lose gps and go into Atti mode what can you count on working vs not working? I am assuming you have only what the camera shows you so you must know your landmarks to fly back to yourself. I assume the map and the direction it indicates is no longer valid. Can altitude be trusted?

3) is there a good source of tips on how to respond to a loss of GPS. I'll go searching now but I came straight here since I saw the original post is exactly what I experienced.

Thanks
Scott

FYI I'm on .500 and 4.0.6 if it matters.

The kp index is a measurement used to measure the geomagnetic storms. I'm not sure if it is very important. But until I has this disconnect I have never flown when it over three. I can't say it caused it but strong atmospheric geomagnetic conditions can cause things like. Pixelated pictures on your tv. Satellite radio interruption on a perfectly clear day. I can't help but believe the it could interfere with the hardware running in the mavic. As for getting it back look at the distance on your remote push your stick foward and turn slowly till the distance starts to drop. That should help you get it back in site.

 

[Flawless]

Kp index will affect you differently depending on your latitude. Closer to the poles, a lower index will affect you more.

I was flying with a Kp index of 6 the other day, without issue. I had less satellites locked (usually around 18, was 11-12) but otherwise fine.

 

[Fletcher500]

The kp index is a measurement used to measure the geomagnetic storms. I'm not sure if it is very important. But until I has this disconnect I have never flown when it over three. I can't say it caused it but strong atmospheric geomagnetic conditions can cause things like. Pixelated pictures on your tv. Satellite radio interruption on a perfectly clear day. I can't help but believe the it could interfere with the hardware running in the mavic. As for getting it back look at the distance on your remote push your stick foward and turn slowly till the distance starts to drop. That should help you get it back in site.

I misspoke earlier. When I said," app and RC are black," I meant to say the GPS data is gone.

Nav back by camera...that would be interesting unless you knew the area. But, good to remember.

Anthony, Regarding your statement, This is where I still have a disconnect. If the GPS is gone, you are not getting a distance from home on either the app or the remote...correct? So how can you determine if the distance is dropping, if there is no GPS data?

 

[rydfree]

No, when the Mavic loses GPS it doesn't know where it is which means it can't keep itself as steady so it will likely drift and not respond as well as it does when it has GPS reception. You'll still have the feed from the camera but you'll need to be much more careful with the controls since the drone can't steady itself using GPS data.

John

New operators seem to panic because they think the Mavic will go into manual mode and it will not respond the same . It never goes into a manual mode of flight . The Mavic responds to stick controls the same without GPS . All GPS does is tell the Mavic to stay put in one spot over the earth even though other factors are trying to push it in different directions , mainly the wind . Without GPS it still self levels and maintains altitude . If there is no wind it actually still maintains position pretty well in Atti mode . All one has to do is move the right stick in the opposite direction than it is being pushed . I agree with the don't PANIC !!! . The thing is still in pretty much an automated state of flight , just not fully automated .

 

[Anthonyk]

I misspoke earlier. When I said," app and RC are black," I meant to say the GPS data is gone.

Nav back by camera...that would be interesting unless you knew the area. But, good to remember.

Anthony, Regarding your statement, This is where I still have a disconnect. If the GPS is gone, you are not getting a distance from home on either the app or the remote...correct? So how can you determine if the distance is dropping, if there is no GPS data?

I can only speak from experience but my distance still changed with stick input.

 

[HFMan]

That's simply not possible if it truly lost GPS. If it actually dropped into ATTI mode due to reasons other than GPS problems, then maybe it actually is possible.