The only issue is that it never stops descending. I could have the drone at 50 feet and if I hold forward on the stick w/o stopping, it will continue to descend and hit the ground, regardless of height. On that last run, I was using at altitude of 20 meters or so. When finished, after letting it climb after moving forward, it was at my height or lower before I left off allowing the brake to kick in. As I mentioned, I"m 6 feet. I understand that there may be deviations plus or minus, but I would assume they would be a few feet up or down, not 10+ with no recovery if that makes sense. Thanks for looking at the logs.
Neither P4P will maintain altitude
- Thread starter jpk1080
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Only if you actually flew below the sea.
There's nothing magical about sea level for a barometer.
The barometer just measures air pressure and the air pressure on land but below sea level is just a tiny bit higher than at sea level.
If your barometer is happy flying at sea level, it will be happy flying a little below sea level.
Besides the lowest point in North America is only -282 ft so you can't have been much below sea level.
Crazy thing is I can go 3km full elevator and not see a drop, if I'm understanding the issues correctly?
Now seeing a drop on a sudden drop is normal and just part of it. But to drop that much without recovery imho is not normal and none of my craft do this.. Mavic, p4,p4p and i2, just to name a few..
Right. I don't remember my others doing this as well including my Inspire, but now they all behave identically. The recovery only comes when the craft is stationary, but even then it doesn't always recover to the height it originally was. On that last flight, it only recovered to about 15 feet though it had started around 25 (according to the vps). Tomorrow I'm heading back to the dealer and hopefully we can try out one of his craft, see how it compares, then figure out what we need to do from there. I was hoping it might be something obvious, or even something I was doing wrong.
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He did mention this issue was less noticeable at higher elevation. Maybe you just haven't noticed when flying low.
So I guess we are in agreement that his flight controller is seeing an abnormal increase in altitude when it's travelling forward or backward (throttle neutral). The question now is this normal no? Anyone else willing to try his test with their P4P and post the logs?
I'm willing, just need a clearing in the weather (maybe late afternoon tomorrow).
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How low is low..? he said it would drop 50' ...when I do testing for long runs I'm under 20m, usually about 18m.
I do a lot of testing for DJI , so I would notice something like this if it was repeatable.. I truly think it's barometer related if it's that excessive.
I can replicate the problem basically at any height. Even if I start at 100 feet, if I continue to hold the stick forward, it will eventually be down at ground level. When I let off, it will climb back up to some random altitude, but normally not what it was originally at. Could there be some issue with the imu's interpreting the barometer data differently causing a conflict?
I know I asked this and maybe it was answered. Does it do this with VPS off?
Can you post a video example with the video caption on? I would like to see what the copter is logging exactly when you see this. This will give an overlay of barometer and VPS..
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So I went out and tested mine and I can't duplicate your issue. However, after review of my logs it looks like blade's hunch is right; something strange is going on with your barometer.
Following Bud's example of plotting velocity and barometer values vs time - Here's a 25s time-frame of mine going full forward:
Here's a snapshot of yours:
Notice how how wild your barometer reading is when compared to mine specifically the immediate increase during acceleration. The controller detects unwanted altitude gain so it counters by adding a negative altitude vector, stabilizing the gain on the barometer when in reality it's actually loosing altitude.
Post edit:
Here's the my flight. Excuse the video artifacts, my Nexus 7 has a hard time handling GO4 app and screen recorder at the same time. Like I said before, nothing to see:
Following Bud's example of plotting velocity and barometer values vs time - Here's a 25s time-frame of mine going full forward:
Here's a snapshot of yours:
Notice how how wild your barometer reading is when compared to mine specifically the immediate increase during acceleration. The controller detects unwanted altitude gain so it counters by adding a negative altitude vector, stabilizing the gain on the barometer when in reality it's actually loosing altitude.
Post edit:
Here's the my flight. Excuse the video artifacts, my Nexus 7 has a hard time handling GO4 app and screen recorder at the same time. Like I said before, nothing to see:
Last edited:
That is very strange. I meant to put this up earlier. Something must have happened by going out west with these for it to affect all of them in the same exact way. How could all barometers be off like this and unable to be fixed?
Alright guys. I flew again today. Before I flew, I did a few things I haven't tried before. I reverted back to the oldest firmware possible, did an imu calibration, upgraded to the next oldest, imu calibration, and finally the newest firmware, followed by a imu calibration and compass calibration. None of this had any affect on the problems I've been having unfortunately. While I was out there, I did a few quick flights up the street. Hopefully this more accurate shows just how quick the drones are descending. I'm at a loss at this point. Thanks for looking.
Dropbox - 2-6-17
Alright guys. I flew again today. Before I flew, I did a few things I haven't tried before. I reverted back to the oldest firmware possible, did an imu calibration, upgraded to the next oldest, imu calibration, and finally the newest firmware, followed by a imu calibration and compass calibration. None of this had any affect on the problems I've been having unfortunately. While I was out there, I did a few quick flights up the street. Hopefully this more accurate shows just how quick the drones are descending. I'm at a loss at this point. Thanks for looking.
Dropbox - 2-6-17
What's the humidity and temp for these flights? All the same or has each day been different? The above video is very extreme and would send my craft in if it was doing this. I have seen drop while transitioning but not FFF like this.
It's varies from dry desert conditions to more humid days in the 60s. He problem is all of them are doing it. It just doesn't make sense.
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There is a slope to the street so it's somewhat exaggerated but it's clear you have a legitimate issue.
Not sure about the barometer DJI uses, but my previous quad with a build-in baro had two small holes on it the chip; You didn't fly through any dust / fog / smoke / rain with your 3 drones right? How did they travel to Palm Springs with you?
I'm with blade, open up a ticket with support, flag one of your flights (Fly129.DAT is good) and send her in.
Not sure about the barometer DJI uses, but my previous quad with a build-in baro had two small holes on it the chip; You didn't fly through any dust / fog / smoke / rain with your 3 drones right? How did they travel to Palm Springs with you?
I'm with blade, open up a ticket with support, flag one of your flights (Fly129.DAT is good) and send her in.
Thanks for the suggestions. They are new so I may try to get the dealer to replace them. Nope I haven't flown them in any conditions other than clear sunny weather. They traveled on a friend of mines semi in a safe compartment. It has a lounge in it and they were kept there. Got them back exactly how they went out.
