Phantom 4 altitude displaying as a negative number

[jimbob81]

Hello. I am new to flying drones. I have had my Phantom 4 for about two weeks and for the most part it has worked great. I have had a couple of glitches that I'm not sure are problems or are just inherent to the operation of the aircraft. The other day I took my Phantom out for a flight and the altitude reading started at 0 feet like normal. I took it up to about 200 feet, flew around a bit and when I started to bring it down I noticed it was dropping on its own pretty rapidly. I regained control and landed safely. I noticed the altitude reading was -30 feet. I didn't think about it much at the time. I wanted to take off again but the message at the top of the screen read 'cannot take off'. I clicked on the message and it said 'IMU altitude exception, contact customer service'. At this point I shut everything down and restarted and everything seemed normal, however I did not push it too hard because I was getting nervous. I called tech support the next day but they where not much help. They insisted that I should have gotten screen shots of the problem while it was happening even though I told them exactly what the error message said. Today I took it out for a flight and all seemed normal but after switching batteries, I noticed that the altitude was saying -160 feet. I had the drone about 100 feet in the air and it was still displaying a negative altitude reading. I also noticed that while I had it hovering it would not keep its altitude stable. It would some times slowly drift up or down. By the way, I have done IMU, compass and transmitter calibrations. I contacted customer service again. Again, no help. Anybody else have similar issues? Is there a problem with my Phantom or is this normal operation?


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[Zuzua]

Example: if you take off from a cliff's edge and descend below the take off level, then you will get a negative height.
So is it possible where you took off from was higher than where you flew at when you got the negative height?

 

[jimbob81]

I was on a baseball field. Totally flat.


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[Zuzua]

I was on a baseball field. Totally flat.


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Definitely it is not normal, if you have done all the calibrations successfully then the issue must be hardware, I'm thinking the barometer maybe?
If it is a recent purchase and you have the option to take it back, that's what I would do. If not I have heard good things are happening at dji repair center in California.

 

[Ibmftw]

@jimbob81 Do not fly that AC sounds like a faulty barometer, send it in to DJI immediately for evaluation. If I were in your situation and DJI wanted to play hard ball and not except it, in this case I would be forced to tell a little lie to and say that the AC is spontaniously ascending and descending 50ft, this will probably fast track them to looking at the baromoter, that for all intents and purposes seems to be one of the components that is struggling in many P4's.

 

[scatmanr1]

Mine is going to service Monday


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[WWK888]

@jimbob81 Do not fly that AC sounds like a faulty barometer, send it in to DJI immediately for evaluation. If I were in your situation and DJI wanted to play hard ball and not except it, in this case I would be forced to tell a little lie to and say that the AC is spontaniously ascending and descending 50ft, this will probably fast track them to looking at the baromoter, that for all intents and purposes seems to be one of the components that is struggling in many P4's.

They might ask for the flight logs to verify that claim.

 

[Tom D - OHIO]

@jimbob81 my P4 did the same as yours during a flight yesterday. I did not take it to 200 feet because the altitude readings were all over the place. Other than that, the P4 flew ok. Did a IMU recalibration (second on after firmware update) to see if it helps. Hope to fly again soon to check it out.


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[MultiBrew]

Was there ever a resolution to this issue? I have the same. I was hovering at about 20 feet to set the POI so I could test that Intelligent Flight Mode. I selected the Point of Interest and got a warning that I must be a minimum of 5m(16ft). When I checked elevation it was -177 feet! I am 20 feet above the exact takeoff point!!

I tried a few times but had the same results. I performed a compass cal with no change. I will do the IMU and firmware update but it sounds like it may be a hardward issue (barometer?). This could be a huge issue for RTH or any of the Intelligent Flight Modes!!

 

[Tom D - OHIO]

Still the same problem here. Have been flying conservatively until a firmware update is available to hopefully get the P4 back to normal.

 

[MultiBrew]

I see another thread where a P4 owner did a factory reset using the DJI assistant and it corrected his issue. Has anyone here tried that yet? Looks like someone else in the thread tried it but it didn't help.

Factory Reset, Update: It fixed my altitude problems!

I will try that before the calibrations since I will need to recalibrate everything after that anyway.

 

[MultiBrew]

Tom, I'm also from Ohio. Are you in northeast Ohio?

Still the same problem here. Have been flying conservatively until a firmware update is available to hopefully get the P4 back to normal.

 

[Tom D - OHIO]

Northwest Ohio........Catawba Island

 

[MultiBrew]

I will be driving right past you on my way to UT. I was there (Port Clinton) a few weeks ago for lunch after the National Matches at Camp Perry! If I get up that way again I'll bring the P4!

Another note about the elevation issue. Today I had the P4 on a picnic table (aluminum just in case that matters). I was looking to do some updating of the firmware. While the Assistant 2 software was downloading I went into the DJI Go app and the elevation was showing zero. However, the "distance" was climbing! It got out to almost 60 feet. The drone was sitting 12" away from the controller!! WTF?!!

At the end of the day (lunch) I was unable to successfully download the Assistant 2 software to the ipad mini 2 so I haven't been able to run a factory reset to see it it helps!

 

[r62ewa]

I will be driving right past you on my way to UT. I was there (Port Clinton) a few weeks ago for lunch after the National Matches at Camp Perry! If I get up that way again I'll bring the P4!

Another note about the elevation issue. Today I had the P4 on a picnic table (aluminum just in case that matters). I was looking to do some updating of the firmware. While the Assistant 2 software was downloading I went into the DJI Go app and the elevation was showing zero. However, the "distance" was climbing! It got out to almost 60 feet. The drone was sitting 12" away from the controller!! WTF?!!

At the end of the day (lunch) I was unable to successfully download the Assistant 2 software to the ipad mini 2 so I haven't been able to run a factory reset to see it it helps!

Correct me if I'm wrong but doesn't the Assistant 2 software have to be installed on a PC not a mobile device?

 

[msinger]

Correct me if I'm wrong but doesn't the Assistant 2 software have to be installed on a PC not a mobile device?

It can only be run on a PC or Mac.

 

[WWK888]

An aluminum table would cause havoc with the compass I would think.


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[MultiBrew]

Good to know about only being able to be installed on a PC (or mac which I don't have). That would explain my frustration with trying to install the Mac version on the ipad mini 2 last night, lol!! Sorry, I am NOT a Mac or Apple person I only own this mini 2 for the P4.

I will finish the install of the Assistant 2 on my laptop then and proceed with the reset and make sure I'm not on an aluminum table when I check it again! Thanks!

 

[MultiBrew]

Did the factory reset. Updated to latest firmware. Next I will calibrate compass and IMU. Is there anything else I should do before my next flight?

Thanks!

 

[FlipFlap]

An aluminum table would cause havoc with the compass I would think.


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Not really. The aluminium is non-magnetic. The only change in magnetic field is possible by inducing voltage and therefore current in the aluminium so those effects are electromagnetic.