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Phantom 4 Drops Altitude
15950 309 2016-4-10 20:53:56
volfi
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Im taking this as a new owner of P3A quite enjoying. Though I do understand the anger in the issue :/ Hope they get a fix ASAP
2016-5-25 05:02:18
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mark.mwilliams7
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volfi Posted at 2016-5-25 14:02
Im taking this as a new owner of P3A quite enjoying. Though I do understand the anger in the issue : ...

Don't get me wrong i love my P4 so much so i sold my P3
2016-5-25 06:09:58
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mark.mwilliams7
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Here's a good one flying along at 13.1 feet 4 mtrs stop it then drops to 7.9 feet 2.4 mtrs!!! WTF

now if your not paying attension would it crash into what ever is under it!!! who's brave enough to try
Phantom4 Drop2.JPG
2016-5-25 06:14:11
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volfi
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mark.mwilliams7 Posted at 2016-5-25 16:09
Don't get me wrong i love my P4 so much so i sold my P3

I see.. *Checks bankaccount* ...

Meaby next month
2016-5-25 06:33:33
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Advocate
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DJI Ken, here's the link to the almost 3gb DAT file from my Phantom 4.  Unfortunately it's rained all day today so I haven't managed to get out and video the altitude drops.  I'm working for the next three days so it'll be Sunday earliest before I get any more info for you.

DAT File
2016-5-25 11:54:36
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darrenwj
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bengalboy69@gma Posted at 2016-5-24 22:34
DJI Ken is correct regarding the gimbal/camera guard causing altitude Yo-Yo in my Phantom 4.  I just ...

I took my gimbal guard off too and it made a difference.  It's much more stable now.  I would have never guessed.  My guard snaps on and off so it probably caused more of a problem during the times when I had it closer to the sensors. It makes sense because although it had issues they weren't always consistent.
2016-5-25 16:53:10
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I've never used a gimbal guard with my Phantom 4.  My thinking is that if it needed one then it would either be an integral part of the design or it would have been supplied in the box by DJI.  I have heard a whisper that this issue is indeed being addressed in an upcoming firmware release, but obviously that's not guaranteed as we have heard the opposite from DJI Ken.  We really need to encourage people to not only post here but also supply DJI with video files and DAT files as it seems that's the only way they'll acknowledge the issue.  I'm tempted to return my Phantom 4 for a refund from Apple and reconsider my options.  The recent price drop of the Inspire is very tempting and it doesn't seem to suffer from this issue so maybe that's an option.  It would mean I'd have to sell my two spare batteries though.  
2016-5-26 01:45:54
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SectorDrone
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MINE DROPS AND I DOES NOT HAVE ANY GIMBAL PROTECTOR...
2016-5-26 02:07:03
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mark.mwilliams7
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SectorDrone Posted at 2016-5-26 11:07
MINE DROPS AND I DOES NOT HAVE ANY GIMBAL PROTECTOR...

please upload a DAT file and get some video, the more we have sent to dji the better
2016-5-26 06:37:43
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mark.mwilliams7
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Hi Ken and Tim

Please see my video from tonight's flight showing the drops when stopping


2016-5-26 11:19:00
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TK-421
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Tip: the author has been banned or deleted automatically shield
2016-5-26 15:44:17
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SectorDrone
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treeboyy Posted at 2016-5-17 12:39
My two cents worth, My P4 for used to drop while stopping and rotating too but after doing the downw ...

Any can confirm Treeboy fix ?
2016-5-26 22:25:40
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I've calibrated everything on my P4 and it still can't hold altitude. The drop when stopping isn't as severe since calibrating but it is still there. Plus I have the drop when hovering problem.

Incidentally DJI Ken posted earlier that the drop after stopping from high speed maybe due to the distance between the ultrasonic sensors and the ground altering due to the rapid tilt of the aircraft when stopping, which initially made sense to me, but on thinking about it it really is a simple geometry problem and shouldn't be the cause of the drops. Looking at that last video it looks like when stopping the P4 compensates for the tilt and doesn't gain altitude from its forward momentum, but drops altitude AFTER it has performed the braking maneuver. Almost like it has assumed that it will have gained altitude whilst stopping so is correcting for that by reducing altitude.

Make sense?

The mathematics of it should be straightforward, and an already solved problem. If you know your altitude and the angle of tilt of the aircraft away from horizontal (whilst stopping) then, assuming a level ground, you can work out what the distance should be between your sensors and the ground, if there is any variation then you have either gained or lost altitude....or the ground isn't level....hmmmm how would you know which? Actually thinking about this is starting to make my head hurt, I'm a Nurse Practitioner not a mathematician or programmer lol.

Anyway, as soon as I can I'm going to take my Phantom 4 out and test it to check definitively whether it still has the drop when stopping, and whether it is still dropping/not maintaining a steady altitude when hovering. I'll capture it on video as best I can using a Canon 5D MKIII on a tripod and an iPhone 6s Plus handheld. Ideally I'd like to synchronize the clocks in all devices so that DJI don't have to hunt around in the DAT file but can go to the exact time any problem arises.

DJI Ken is there any way to check/alter the clock in the Phantom 4?

Sorry for the long post everyone, I do have a habit of wandering off on a tangent!
2016-5-26 23:53:29
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mavs88
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Well DJI (friends) just now I checked again and my Phantom 4 also looses altitude and regains and drifts (just a little bit, but too much). The same happened after a 3rd firmware update of the Phantom 3 Pro which I owned before. The 4th firmware update made the Phantom 3 solid as a rock. I do hope DJI is taking this (and the (iOS)app-problem since 2.8.2) SERIOUS... I would like to fly in a nice and usual SAFE way before DJI will come out with the Phantom 5 or S or SE

Regards,

Max

Phantom 4 and RC all latest update
Apple iPad Pro 9.7" (iOS 9.3.2 final)
2016-5-27 07:30:31
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Phantomski
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How interesting.. you would think that with gps, barometer and other sensors, this would not happen...  Does that "dropping while stopping" happen at every altitude? Most pilots know that braking required more power... I can maybe see that braking at top speed may run out  of power and sag a bit, but not at low speeds and just stopping.. What happens if someone reverses and tries to just start going backwards? would it first dip then overshoot altitude?
Could there be 2 versions orf props, or something like that?
This is quite strange! Especially comparing to my P3, which is quite solid, yet has a weaker power plant...
Hope DJI get this fixed.. flying low over trees and then stopping.. well, it could end badly....
2016-5-27 07:43:52
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mactech
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Advocate Posted at 2016-5-27 03:53
I've calibrated everything on my P4 and it still can't hold altitude. The drop when stopping isn't a ...

They have enough data from all over the web and surely they can sample their own supply of drones to see this is a real issue.  

Them asking for more flight data is a stalling technique and a waste of your time.

Mine does this and just about every P4 out there does it.   Oddly mine does not suffer the issue as often when flying in reverse.
2016-5-27 07:54:56
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mark.mwilliams7
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SectorDrone Posted at 2016-5-27 07:25
Any can confirm Treeboy fix ?

I can safely say the it didn't work for me!
Calibrated everything again still drops just as bad
2016-5-27 11:40:15
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Advocate
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I was hoping to get out with my P4 and get some video evidence and up to date dat files over the weekend but so far I haven't been able to. It's probably going to be Sunday and more like Tuesday before I manage to now. I hate it when real life interferes with my hobbies lol.
2016-5-27 13:40:42
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mavs88
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xjoeyx@satx.rr. Posted at 2016-5-20 00:32
CERTAINLY!  I am COMPLETELY updated on aircraft firmware, remote control firmware, as well as the l ...

I do have the same problems...
May I ask you what YOU think the cause could be?
Regards,
Max
2016-5-27 23:43:20
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karol.kearney
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Dji Ken got my new p4 today and it drops in height when I stop how can this be fixed
2016-5-28 08:16:48
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mark.mwilliams7
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karol.kearney Posted at 2016-5-28 17:16
Dji Ken got my new p4 today and it drops in height when I stop how can this be fixed

Please upload the DAT file from your P4 the more we give Dji the better chance we have of them fixing it.

To get the DAT file you will need to connect your P4 to a PC to get it, download the software from the Dji website on the P4 page under downloads
2016-5-28 11:20:23
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Advocate
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Well, I managed to get out tonight with my Phantom 4, the first time since DJI Go was updated, and it performed admirably.  The altitude drop when stopping was 2-3 feet at most and the Phantom 4 slowly regained this drop after stopping.  It also never once dropped altitude whilst hovering.

One thing I did notice in the updated DJI Go app is that it now displays the altitude from the Ultrasonic sensor as well as the barometric sensor, and there is a difference of around 6 feet.  While the Ultrasonic sensor was showing 6 feet the barometric sensor was showing 13 or more feet.  I would have thought that the Ultrasonic sensor could be used to correct the barometric sensor realtime couldn't it?
2016-5-28 12:25:22
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parkgt
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Where are all the people that said over a month ago that this was an easy fix?  Where are the DJI reps that said they were working on this?  Two months in with no fix!
2016-5-31 15:28:23
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SectorDrone
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DJI just corrected their MISTAKE in recent DJI GO losing Video feed.   But did not fix the crucial and dangerous altitude dropping...in thier latest FW

2016-5-31 16:24:30
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SectorDrone
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Stilll waiting...for the fix...
2016-6-3 07:39:31
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hallmark007
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Mine was fixed with firmware using sport mode my P4 if anything will slightly rise when coming to a halt and for me this was a major change in firmware, well done DJI
2016-6-3 08:23:40
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DJI-Ken
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SectorDrone Posted at 2016-6-3 23:39
Stilll waiting...for the fix...

I replied to your other post in a different thing with the same thing you posted.
You do have a P4 correct?
Can you please get a quick video clip of what you are experiencing.
2016-6-3 08:33:25
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DJI-Ken
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hallmark007 Posted at 2016-6-4 00:23
Mine was fixed with firmware using sport mode my P4 if anything will slightly rise when coming to a  ...

I tested a bunch of P4's yesterday on the new firmware and they all flew great.
There was just a slight rise then dip from full speed Sport mode to a stop. But it was only 3-5ft so that's great.
2016-6-3 08:35:37
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cayalag
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DJI-Ken with the previous version of the firmware my P4 was rock solid, never dropped altitude when stopping... with the new 401, I am suffering the altitude loss...
2016-6-3 09:47:21
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Aardvark
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Competition time..........Place these words in the correct order "Tin, Worms, Of, Opened, Another", any prize from the top shelf (Sorry the Gorillas spoken for).
2016-6-3 11:26:48
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DJI-Jamie
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As Ken has mentioned, we had tested multiple P4 units with the latest firmware and software on both the app and mobile devices and they did not show an extreme altitude drop. There was a noticeable rise in altitude when let go from full speed and then some lowering to compensate from the rise. If everything is updated firmware and software rise, here are some things to consider:

- Ease into the brake, do not let go of the Elevator stick instantly.
- Lower your brake setting

If you are flying in Sport Mode, the rise and fall of the unit is more apparent due to the speed. If this does not help, any video submissions provided should also show the stick commands on the RC, the OSD information in the GO app and the brake settings.
2016-6-3 12:12:49
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DJI-Ken
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cayalag Posted at 2016-6-4 01:47
DJI-Ken with the previous version of the firmware my P4 was rock solid, never dropped altitude when  ...

Follow Jamie's suggestions.
Also, I will not know if you respond to a post of mine unless you reply to one of my posts.
2016-6-3 12:26:22
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cayalag
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DJI-Ken Posted at 2016-6-4 04:26
Follow Jamie's suggestions.
Also, I will not know if you respond to a post of mine unless you repl ...

Ok ! I will try to record some videos for you guys
2016-6-3 23:10:41
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ridge11103
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DJI-Ken Posted at 2016-6-3 21:26
Follow Jamie's suggestions.
Also, I will not know if you respond to a post of mine unless you repl ...

Hi Ken. Since I updated to the 401 fw on my Ph4 I find a slow but (fairly) steady drop in height. This is new, and disconcerting. With the old fw I had no problems of height gain or loss, and remarkable in-flight stability.

I have tried to download a test flight record (just an auto takeoff, then no control inputs until the Ph4 touched the ground and carried on trying to fly, juddering on its skid.) I left the Assistant running for 20 minutes, but nothing came out, so I assumed a bug somewhere (iMac OS 10.10.5 Yosemite).

I would like to revert the fw, but can't find any way to do so (Assistant tries, but reports "Failed" after downloading 100%). I would appreciate any help that DJI can offer.
2016-6-4 03:35:07
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Aardvark
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It may have reverted.....When you check in DJI GO which version does it say you are running there (General settings menu, down at the bottom click on 'about')? (Check with all plugged in and switched on as if ready to fly (No props needed )
2016-6-4 04:00:25
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ridge11103
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Aardvark Posted at 2016-6-4 13:00
It may have reverted.....When you check in DJI GO which version does it say you are running there (G ...

I wish it had reverted! But no - I was running 401 still and was up to date - no red triangle. It seems to me that DJI have withdrawn the previous fw version, so it's not available to revert via DJI Go. It's still there if you use Assistant, but for me Assistant doesn't work.

Bummer - I was really happy with the P4 performance, but now I've had a big loss of trust and confidence in DJI. I think the problem is to do with the fix to the Auto-Track altitude issue: they've messed with some aspect of the IMU which has had ramifications. It's complicated!
2016-6-4 12:09:44
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DJI-Jamie
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ridge11103@btin Posted at 2016-6-5 04:09
I wish it had reverted! But no - I was running 401 still and was up to date - no red triangle. It  ...

We would need to see video footage of what you are experiencing. Again, any video submissions provided should also show the stick commands on the RC, the OSD information in the GO app and the brake settings.
2016-6-4 12:27:14
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Aardvark
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ridge11103@btin Posted at 2016-6-4 21:09
I wish it had reverted! But no - I was running 401 still and was up to date - no red triangle. It  ...

Only thing I could suggest using Assistant 2, is to try it with fastest broadband you can connect to, and if fails close down and restart Assistant2. Seems to depend on how busy the DJI server is (But I could be wrong ).
2016-6-4 12:31:38
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DJI-Ken
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ridge11103@btin Posted at 2016-6-4 19:35
Hi Ken. Since I updated to the 401 fw on my Ph4 I find a slow but (fairly) steady drop in height.  ...

That is strange that you see an altitude adjustment after updating.
So you are saying that when you do an auto takeoff after it hovers it lowers back down to the ground?
And on your Mac, you installed the driver as well? You have to install the Assistant2 and the driver.
As Jamie said, a quick video would be great.
2016-6-4 12:59:18
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skyeboysteve
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DJI-Ken Posted at 2016-6-5 04:59
That is strange that you see an altitude adjustment after updating.
So you are saying that when y ...

FWIW, I sent my P4 back to DJI in California.  The day after they received it, I got a notice that my unit was being sent back--no explanation was given.

A few days later, to my pleasant surprise, I got a new P4 (at least a different serial number than the one I had before, which also needed activation for registration when I first fired it up).  It was however, covered in black greasy fingerprints, and black grease was also found inside the Styrofoam case--so it made me wonder if the DJI repair techs also work on their cars at the same time--but I'm not complaining; as this model HAS no altitude drop issue!  Flies perfectly!  The video compression is horrible though for anything other than "none" for the "color" setting--at least when set to d-log or vivid.  Used to be that only d-log was really bad, but at least with the "none" setting, the compression is actually giving superior quality now than I get on my two P3Ps--that wasn't the case with the first P4.  The first P4 (with altitude drop issues) had inferior video on all settings compared to my P3Ps.  Anyway, this video compression improvement may have been fixed by the latest firmware update, and not so much the new aircraft; as I didn't think to test the video quality before I upgraded the firmware.

Anyway, for those still having altitude drop issues, try asking DJI for a replacement. The three times I've sent a unit into customer service, they've been great--very fast turn around times at least; though not very communicative; but I'd rather see results than lots of hot air anyway.  The only thing I wasn't happy about was all the dirty fingerprints on both the new P4 and my original RC.  Took almost an hour to carefully scrub those off--especially on those spongy rubber grips of the RC.
2016-6-4 19:13:32
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