Hello. I'm hoping i have an issue someone can help me address. I was recently out in Palm Springs flying both of these drones on a project I'm involved in. I noticed that one of my P4P would not maintain altitude. If you hold forward on the right stick, it would literally over about 200 feet crash into the ground from about 20 feet if I do not intervene. I tried everything; imu calibration, all settings to default, compass calibration, etc. No luck. I then noticed that my other one did the exact same thing. Neither can maintain altitude regardless of mode. I did the same thing to this one as well with no luck. I called DJI but they had no clue. I also fired up my Inspire 1 thinking maybe it's some kind of glitch, but it too did the same exactly thing. After some trouble shooting, I realized that I was actually below sea level. I thought this was surely the issue as it affected all three drones. Fast forward to today, when I'm back at home (800 ft msl), and they are doing the same thing. I again redid the imu calibration and compass, but neither fixed anything. I can't figure out what could be going on here. Do I have some rogue setting selected on all of these that is causing an issue? I have tried with sensors on, off, etc but to no available. I'm not sure what to do at this point honestly. Any help much appreciated. Thanks.

I hope it isn't caused by being below sea level because I live in Cali too and there are lots of places below sea level. There has to be lots of people flying below sea level some times. I would say has to be something external to be happening to all three drones though. Unless you are using the same controller for all? Or same Dji go device? phone? tablet. Switch that out.

Yeah. I thought it was a bug in the software possibly causing an issue below sea level but I confirmed today, that it's still doing it at home. The problem is, it's also doing it on the Inspire making it even more hard to diagnose. If you have your hands off the left stick and literally just push forward, it will just descend while moving forward until it impacts the ground. I stop it before that happens of course but none of my other drones have done this. They all have different controllers. I have tried my phone, and two different ipads. If you take yours outside right now and just push forward on the right stick, it should maintain altitude correct?

Visalia Califor Posted at 2017-2-2 14:16
I hope it isn't caused by being below sea level because I live in Cali too and there are lots of places below sea level. There has to be lots of people flying below sea level some times. I would say has to be something external to be happening to all three drones though. Unless you are using the same controller for all? Or same Dji go device? phone? tablet. Switch that out.

And you mention IMU and compass calibration, but what about VPS? I assume yes, but you didn't say...

Can you calibrate the VPS? Here is the issue. The vps seems fine. I mean below sea level, I was still getting positive numbers, I assume based on ground height. The thing is, the gps and vps would start at the same height, then be wildly different after moving 100 feet in any direction. Then when you would bring the drone back to you and let it hover, it would slowly ascend. Like it knew it was lower than it should be. It wouldn't match back up though until you landed, and took back off.

fans6a59eb5c Posted at 2017-2-2 14:32
Can you calibrate the VPS? Here is the issue. The vps seems fine. I mean below sea level, I was still getting positive numbers, I assume based on ground height. The thing is, the gps and vps would start at the same height, then be wildly different after moving 100 feet in any direction. Then when you would bring the drone back to you and let it hover, it would slowly ascend. Like it knew it was lower than it should be. It wouldn't match back up though until you landed, and took back off.

The GPS has no bearing on height, the altitude of the aircraft is measured by a barometric device, not GPS. And the aircraft has no knowledge of sea level or anything else, it simply measures it's altitude in relation to the point at which it took off.

While barometric sensors are reasonably accurate, minor changes in air pressure can alter the readings. When you say the aircraft lost height ove a 200 feet distance, could it be that the ground was gently rising? If so, the aircraft has no knowledge of that. And the VPS system is based on sonar, and only kicks in at 10 feet altitude or less.

The problem is, all these areas have been almost perfectly flat (race track). It's such a quick dive that it's def. not the terrain rising in one direction or another. They do hover find without losing or gaining too much altitude.
Just to add you can literally hold the right stick in any direction and it will immediatelyi, take off and try to run itself into the ground with 100 feet or so. Doesn't matter if the sensors are on or off.

I was near an airport in California. I got prior authorization so the Geo was turned off. I would occasionally get messages saying it would go into hover but never actually would. The issue is, I tried it in other areas out there that were not near airports. I also live on the other side of the country, where I am now, and not within close proximity to any airports. Could the barometers somehow have been damaged out there flying below sea level. I too have no ideas honestly has all 3 are affected. I have had the inspire for over a year and do not recall this ever happening as it's so noticeable, especially down low.

I can do that through the dji assistant app?

fans6a59eb5c Posted at 2017-2-2 16:04
I can do that through the dji assistant app?

You could try calibrating the sensors using 'DJI Assistant 2' from Here

That may help stabilise things at 10m and below, and possibly above.

fans6a59eb5c Posted at 2017-2-2 15:08
I was near an airport in California. I got prior authorization so the Geo was turned off. I would occasionally get messages saying it would go into hover but never actually would. The issue is, I tried it in other areas out there that were not near airports. I also live on the other side of the country, where I am now, and not within close proximity to any airports. Could the barometers somehow have been damaged out there flying below sea level. I too have no ideas honestly has all 3 are affected. I have had the inspire for over a year and do not recall this ever happening as it's so noticeable, especially down low.

The barometer simply measures air pressure, it has no idea what sea level means, so it cannot be damaged in that way.

Thanks for the info. I gave the calibration a shot through the dji assistant app. I will try flying it again tomorrow but based on what i've tried already, i'm not putting too much faith in things working correctly.

Yeah. Different purposes.

Please sync the flight records from DJI GO app first.
And provide me with the DJI account email and the exact date and time this occurred.
I'll help to look into it.
Is your DJI account email address the same as your forum email?

Thanks Mindy. Yes it should be jpk1080@hotmail.com. I will try to sync the records this morning, but this will be on just the one drone. All of them have the same issue. I experienced this issue again at home on 2-2-17. The last time I flew was when I was in Palm springs, below sea level, which would have been 1-13-17 thru 1-27-17. Thank you.

Flight Logs synced for the last month. Let me know if I can do anything else to help Mindy. I appreciate it.

Here is a link to the flight dat. files i uploaded today. The first one was me just testing to see if the drone was still doing the same thing after calibrations, resets, etc. The second was what you asked for which consisted of hovering, climb, descend, and going in each direction. The drone would descend in all directions by about .4 to .7 fps. I hope it indicates that on the logs. Thanks for the help. Let me know if I can get anything else for you. I was unsure of how to pull the controller logs off the ipad.

https://www.dropbox.com/sh/ujyf1 ... anDf5E_ATqdkya?dl=0

Okay I went out and did a few different test on a field. The first few, are what you asked for. The last one, is just a simple hover, followed by forward, and back. As you can see, there is a drop off on the field a little ways. After going forward, and letting it hover, you will see it climb. That is not me adjusting the height. It is climbing itself almost as if it knows it descended. At these heights, the gps and vps will be significantly off from one another until it regains its altitude. You can tell from the video that the drone is descending both forward, and backwards. Up at altitude, it doesn't seem to be as much of an issue. Thanks for taking a look.

One more thing, the other P4P and Inspire 1 do the exact same thing to the T.

https://www.dropbox.com/sh/xo03i ... qVxmIFS4BeMgca?dl=0