P3P Barometer

KachemakDiver

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Clearly this isnt a common issue with P3's and its not really a big deal. It's only noticeable and annoying at very low altitude which is not usually where we fly. Was just wondering if anyone has had this issue and knew of a fix.
I’m doing some research about this issue now.
It may be helpful if you download the log files.
 

Oso

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Clearly this isnt a common issue with P3's and its not really a big deal. It's only noticeable and annoying at very low altitude which is not usually where we fly. Was just wondering if anyone has had this issue and knew of a fix.
This has actucally been reported many times over the years. You can see several of them in the search linked below. I myself have had the issue ever since updating to FW 1.2.x on both of my P3s. Prior to that FW, hover altitude for me was rock solid but it was instantly lost with that FW update. Ever since then, if I hover at up to 10-12 feet or so, it will slowly drift lower and lower and lower. This is one of the common symptoms when people have reported the issue. No amount of IMU calibrations, cold or not, have ever made a difference for me. Nor has VPS being on or off, or switching mobile devices / app versions. However, if I raise the hover to say 20 feet or so, it then stops the slow drift down and will keep a steady altitude. This is true on both my P3P and my P3A and I learned to live with it after a short while.

 
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This has actucally been reported many times over the years. You can see several of them in the search linked below. I myself have had the issue ever since updating to FW 1.2.x on both of my P3s. Prior to that FW, hover altitude for me was rock solid but it was instantly lost with that FW update. Ever since then, if I hover at up to 10-12 feet or so, it will slowly drift lower and lower and lower. This is one of the common symptoms when people have reported the issue. No amount of IMU calibrations, cold or not, have ever made a difference for me. Nor has VPS being on or off, or switching mobile devices / app versions. However, if I raise the hover to say 20 feet or so, it then stops the slow drift down and will keep a steady altitude. This is true on both my P3P and my P3A and I learned to live with it after a short while.

Thanks @Oso
Glad to hear its a known issue with FW. I'm running the latest version so thats definitely it. Exact same symptoms as you describe. Now that I know I'll just keep on living with it. At least now I know its not hardware failing.
 
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Have you tried to do an auto takeoff to see if it still does it?
I've never done an auto takeoff ever, nor do I like to autoland. I find the auto landing is abit harsher than my manual landings. Thanks for all your suggestions. Apparently it's an issue Im just going to have to live with.
 
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Oso

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I've never done an auto takeoff ever, nor do I like to autoland. I find the auto landing is abit harsher than my manual landings. Thanks for all your suggestions. Apparently it's an issue Im just going to have to live with.
Autolanding became hard and abrupt for me with the very same FW version that created the hover altitude issue I mentioned earlier. With the prior FW, autolandings were silky smooth and I used to enjoy demonstrating that feature for friends who were always amazed. No more autoland demonstrations after that FW update since the AC would now suddenly hit so hard. Oddly, the P3S has the wonderfully smooth autolanding and several people have posted here asking why their P3A or P3P did not land as smoothly as the P3S they were upgrading from.

That particular FW update also introduced terrible instability when using VPS, so most of us needed to disable VPS as a work around. It also introduced lines on 4:3 pictures so we had to use 16:9 only as a work around until the fix for that came out only 3 days later. That was an exciting FW update back in June of 2015. Good times.
 
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Autolanding became hard and abrupt for me with the very same FW version that created the hover altitude issue I mentioned earlier. With the prior FW, autolandings were silky smooth and I used to enjoy demonstrating that feature for friends who were always amazed. No more autoland demonstrations after that FW update since the AC would now hit so hard after the FW update. Oddly, the P3S has the wonderfully smooth autolanding and several people have posted here asking why their P3A or P3P did not land as smoothly as the P3S they were upgrading from.

That particular FW update also introduced terrible instability when using VPS, so most of us needed to disable VPS as a work around. It also introduced lines on 4:3 pictures so we had to use 16:9 only as a work around until the fix for that came out only 3 days later. That was an exciting FW update back in June of 2015. Good times.
Wow almost glad i missed those days lol. My refurbished P3P came directly from DJI when I bought it already loaded with the last version. Everything you mentioned explains alot. Oddly my beat up P2V+ hovers and autolands better than my P3. Now I know why. Also, the P3S is a very different bird, including electronically. Different FW completely. Explains why it still doesn't have these issues.
 

KachemakDiver

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I don’t auto either, always have landed manually. My P3P hovers very well at 6 feet and I have the latest firmware version. Below 6 feet it drifts a tiny bit but easily managed.
I like having complete control of my bird.
Thanks @Oso for the information.👍
 
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Hmm, I never saw this anomaly in my P3P.

The good ole days......I do remember around the end of 2015 there was version 1.5 firmware that allowed many drones fall from the sky, due to battery getting too low on full acceleration. When DJI LiPo batteries get below 3.0V they shut off, to protect themselves from damage. Hah! Forget the drone, we're protecting the battery. This mostly happened in cold weather, and when the drone was launched with a "less than full" charge. That was fixed with 1.6 firmware. The solution was to invoke auto dethrottling after the voltage got down to 3.6V. When one of the cells reached 3.6, you no longer had full throttle, it was restricted to keep the voltage above 3.0V until the end of the flight. Version 1.6 is the firmware I stuck with until I sold the craft about 9mos ago.

I would have certainly noticed this issue the OP mentions because I would hover at 6' all the time when landing, sometimes a full minute before I would walk over and hand catch, which is how I landed 90% of the time. It's really odd that some craft have this anomaly and others don't. @3rdof5 , have you tried to reset the drone using DJI Assistant? If you're looking to experiment, that's what I'd try next. I'm wondering if DJI may have gotten a bad batch of barometers that cause this anomaly.

I also never used auto land because the descent was too fast.
 
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Hmm, I never saw this anomaly in my P3P.

The good ole days......I do remember around the end of 2015 there was version 1.5 firmware that allowed many drones fall from the sky, due to battery getting too low on full acceleration. When DJI LiPo batteries get below 3.0V they shut off, to protect themselves from damage. Hah! Forget the drone, we're protecting the battery. This mostly happened in cold weather, and when the drone was launched with a "less than full" charge. That was fixed with 1.6 firmware. The solution was to invoke auto dethrottling after the voltage got down to 3.6V. When one of the cells reached 3.6, you no longer had full throttle, it was restricted to keep the voltage above 3.0V until the end of the flight. Version 1.6 is the firmware I stuck with until I sold the craft about 9mos ago.

I would have certainly noticed this issue the OP mentions because I would hover at 6' all the time when landing, sometimes a full minute before I would walk over and hand catch, which is how I landed 90% of the time. It's really odd that some craft have this anomaly and others don't. @3rdof5 , have you tried to reset the drone using DJI Assistant? If you're looking to experiment, that's what I'd try next. I'm wondering if DJI may have gotten a bad batch of barometers that cause this anomaly.

I also never used auto land because the descent was too fast.
Actually as OSO explained, this issue only presents itself if you take off and never climb over 20 to 30 feet. Once above that the issue disappears and hovering is normal and since most people always do climb higher during flight they would never notice it. Coming back down after flight and hovering at 6 feet will be stable.
 
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Coming back down after flight and hovering at 6 feet will be stable.
Hmm, that's interesting. But still, with over 1 million feet (190mi) of flight time on my P3P, I think I would have still noticed it during all my initial testing and low flight training exercises in the beginning. However, I did notice my altitude telemetry numbers varying up to 40' difference when hovering at 6' altitude. These differences were noticed 15min apart, from take-off to landing. I don't think natures barometric pressures would change that much in California's mild climate in just 15 min, but I may be wrong.

I was always amazed how well the P3P flew, great range, good video and photos. Great memories. Back then I even flew the statue of Liberty.

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