I had a major scare this past weekend and nearly lost my mavic. I was attempting to take some pictures inside a gorge where the GPS signal was poor (no lock). I was all ready to accept and control the fact there was no GPS.
I took off from the side of the gorge and then dropped down into what is negative altitude. As soon as I moved over into the gorge, the computer said I've reached maximum altitude!! I did have the VPS on so i figured it was due to this. I tried to get the mavic to ascend and come back to me, no luck!!! It would not raise itself and I felt that I was going to loose it in the gorge. Eventually I decided to hike dow to a lower level and carefully move the mavic along the gorge to get there. I would then move the mavic to an area it could descend.

As some point I did think this was due to the sensors so I tried to disable all the VPS and the system went into Atti mode but it would still not let me ascend.

Questions....

Will the Mavic automatically lower itself if no GPS or VPS is active and it sees it is higher from the ground than it likes?
If VPS is turned off mid flight, why doesn't the aircraft then be allowed to ascend? I tried to do this but no luck.
What is the actually max altitude with GPS and with and without VPS?

Is there a problem in progrogramming or an improvement needed to make these decision systems better?

Regards,
Jeff

This sounds like you took off somewhere in the gorge, or reset the home point to somewhere in the gorge at some point.  That would limit the altitude you could climb to get out of it.  Home point should have been at the top if you expected to fly it back there.  Did you restart the drone while in the gorge?

Negative flight altitude is something that is going to happen to me too - I plan on taking off shore or precipices 20 to 100 meters above sea/ground level below, and then flying down.
It would be nice to hear from DJI a confirmation that this is something that Mavic handles gracefully.

Upload the (TXT file) log from the flight to PhantomHelp using these instructions and provide a link and we'll take a look.

Without having seen the log data I'd guess that the real key to understanding what happened is the fact that the Mavic firmware more severely limits your height range while you're flying in ATTI mode, which is consistent with your comment that "there was no GPS" while you were flying inside the gorge. In other words, the normal maximum altitude setting you see and can modify in the Go app is ignored when you're in ATTI mode and the limit that is used is much more restrictive. In any case, providing the log data is likely to shed a bit more light on what happened.

DroneFlying Posted at 2017-8-2 05:00
Upload the (TXT file) log from the flight to PhantomHelp using these instructions and provide a link and we'll take a look.

Without having seen the log data I'd guess that the real key to understanding what happened is the fact that the Mavic firmware more severely limits your height range while you're flying in ATTI mode, which is consistent with your comment that "there was no GPS" while you were flying inside the gorge. In other words, the normal maximum altitude setting you see and can modify in the Go app is ignored when you're in ATTI mode and the limit that is used is much more restrictive. In any case, providing the log data is likely to shed a bit more light on what happened.

I think uploading it is a waste of time. I think what you and he said is exactly what happened. It was in ATTI mode and wouldn't go up. I've had it happen to me several times in this park by me. I can't imagine if it was a gorge.

jeebs-9 Posted at 2017-8-2 05:28
I think uploading it is a waste of time. I think what you and he said is exactly what happened. It was in ATTI mode and wouldn't go up. I've had it happen to me several times in this park by me. I can't imagine if it was a gorge.

I think uploading it is a waste of time.

Not really.  All we have is conjecture at this time.  The log will either support or disprove.  

Regarding VPS - It has nothing to do with maximum height warnings.  

When you have little or no gps, you will always get a warning of max height I think it's 16 ft.

As far as im aware the mavic uses the barometric altitude not GPS or VPS for max altitude and so on so it shouldn't have any effect if it switches to ATTI.
As above, upload the logs.  Its the only way to see if theres a bug or not.

OK, i added my file information. Can someone help interpret? To me it appears that since I was in ATTI mode and I moved off to a deeper area, it was stuck using the max height of the VPS even after i turned that off since I started the flight with it? Was that possible? Could switching to sports mode in the future help make sure you will at least get the 100 ft of height? I'm not clear how the altitude sensor will even work. Does it take a barometric pressure reading at launch and then use the delta off that? In which case, I would wonder how sensitive it really must be to notice 100 ft!

http://www.phantomhelp.com/LogViewer/TBUMQ428OMNCOUMYAJBQ/#

jtt777 Posted at 2017-8-6 10:36
OK, i added my file information. Can someone help interpret? To me it appears that since I was in ATTI mode and I moved off to a deeper area, it was stuck using the max height of the VPS even after i turned that off since I started the flight with it? Was that possible? Could switching to sports mode in the future help make sure you will at least get the 100 ft of height? I'm not clear how the altitude sensor will even work. Does it take a barometric pressure reading at launch and then use the delta off that? In which case, I would wonder how sensitive it really must be to notice 100 ft!

http://www.phantomhelp.com/LogViewer/TBUMQ428OMNCOUMYAJBQ/#

Can you try uploading it again? I'm not able to view the log details.

jtt777 Posted at 2017-8-6 10:36
OK, i added my file information. Can someone help interpret? To me it appears that since I was in ATTI mode and I moved off to a deeper area, it was stuck using the max height of the VPS even after i turned that off since I started the flight with it? Was that possible? Could switching to sports mode in the future help make sure you will at least get the 100 ft of height? I'm not clear how the altitude sensor will even work. Does it take a barometric pressure reading at launch and then use the delta off that? In which case, I would wonder how sensitive it really must be to notice 100 ft!

http://www.phantomhelp.com/LogViewer/TBUMQ428OMNCOUMYAJBQ/#

P51 of your manual, your height is restricted to 16 feet 5 metres when gps signal is weak, this is why you couldn't ascend, the warning was clear, you can no longer raise AC above 16 ft if you have none or weak gps.

Uploaded it again and the same issue... does it now show anything there because there is no GPS data? If you download the CSV file you can see there is data

I agree if no GPS you can be restricted to 16 ft but what about when i disabled VPS, why was I still restricted?

Also, i think the manual's explanation is horrible. It doesn't cover the scenario of flying down into something or off a balcony.

jtt777 Posted at 2017-8-6 14:59
I agree if no GPS you can be restricted to 16 ft but what about when i disabled VPS, why was I still restricted?

Also, i think the manual's explanation is horrible. It doesn't cover the scenario of flying down into something or off a balcony.

Hey it's a poor excuse mentioning what you read in the manual, because you definitely missed the bit in the manual where it tells you to make sure you have gps before flying. If VPS is turned off then your height is measured by barometer.
We all make silly mistakes one time or another but we have to accept responsibility

who died and made you king? thanks a lot hallmark007 for being another great internet troll ass. your attitude is so lovely. go get banned from this forum and bestow your "wisdom" elsewhere

The manual doesn't say never fly without GPS. Also it doesn't say the drone would revise observed max height (ended up at negative)  if the the drone is moved so that the floor "disappears". a better programming approach would be to limit height to the max take off height observed intitally with VPS if it was on so you could still see positive values. that needs to be much more implicit in the manual. As written, it provides a picture of someone in a building with no GPS trying to rise from ground more than 16 ft.

Also, there needs to be a proper ATTI mode honestly. coming from a phantom 3, this is a disappointment.  lastly, the barometer doesn't seem to limit max height if you start off a flight with VPS. I turned VPS off when i saw the issue and i was still stuck at ~16 ft. The barometer should limit height to 164 ft above takeoff point based on what i've been reading IN THE MANUAL if no GPS and no VPS. It may only use the barometer to control altitude, not limit it. Maybe the barometer is not accurate enough? Hope DJI could verify vs. some troll.  This is a programming problem as i see it.

jtt777 Posted at 2017-8-6 15:44
who died and made you king? thanks a lot hallmark007 for being another great internet troll ass. your attitude is so lovely. go get banned from this forum and bestow your "wisdom" elsewhere

The manual doesn't say never fly without GPS. Also it doesn't say the drone would revise observed max height (ended up at negative)  if the the drone is moved so that the floor "disappears". a better programming approach would be to limit height to the max take off height observed intitally with VPS if it was on so you could still see positive values. that needs to be much more implicit in the manual. As written, it provides a picture of someone in a building with no GPS trying to rise from ground more than 16 ft.

Obviously no responsibility so, you took off in Atti mode flew over a ravine not knowing what you were doing, things go wrong and you pick the part of the manual that suits you, but if you want to choose that option then you should read the manual properly, not pick and choose the bits that might suit you,

I think the only one of us breaking forum rules is you with your personal insults, truth hurts some just can't take it go learn how to fly.
Goodbye....

jtt777 Posted at 2017-8-6 14:50
Uploaded it again and the same issue... does it now show anything there because there is no GPS data? If you download the CSV file you can see there is data

You're right about it not showing the map because of a lack of GPS data. I was expecting there to be some GPS coordinates because you mentioned that the flight started above the gorge and I'd have expected there to be a GPS signal there but no matter.

Looking at the data it shows VPS height readings throughout the flight, which tells me that VPS was enabled. If VPS had been disabled you'd see 0 values in the VpsAltitude columns, but they contain non-zero values which indicates that it was enabled. That in turn explains why you weren't able to ascend: because whenever VPS is able to detect a height that's what will be used in place of the barometer, since it's generally going to be a little more accurate than the barometric-derived value.

Even if you had disabled VPS there's no guarantee you'd have been able to ascend, because again the barometer's not always a very accurate indication of (home point) AGL height. I guess the moral of the story is that if you can't avoid going into ATTI mode that you should start the flight from the bottom of the location and fly up as needed. I realize that probably wasn't a convenient option here, but the bottom line is that descending into a place where there's no GPS is a risky endeavor.

hallmark007 Posted at 2017-8-6 16:19
Obviously no responsibility so, you took off in Atti mode flew over a ravine not knowing what you were doing, things go wrong and you pick the part of the manual that suits you, but if you want to choose that option then you should read the manual properly, not pick and choose the bits that might suit you,

I think the only one of us breaking forum rules is you with your personal insults, truth hurts some just can't take it go learn how to fly.

Two of the helpful individuals on the entire forum in here trying to lend a hand and all he can do is yell at you. Brilliant.

These are not toys. Learning and a good acquaintance with common sense is required to not have a bad time. I'm not sure why I'm even still surprised; we sell tiny flying blenders at Best Buy where the only barrier of entry is how much one has in their bank account, and there is still the expectation of general intelligence and grace.

This is just downright attitude. hallmark007 is not helpful but condescending. there is no need for attitude and assumptions and people aren't being responsible and knowledgeable of what they are doing. i'm an extremely responsible flyer who's logged many miles safely and encountering peculiarities with the behaviour of a mavic pro in non GPS conditions.

what a downright hostile group. i have no need to explain any more to the bullies on this forum. i can't belive then ephentz joined in on the rant of assuming all sorts of stuff about who is writing on here and what they value. Go ahead with your blanket assumptions and feel better about yourself instead of embracing others than also enjoy this hobby.

all i wanted was some decency in helping to troubleshoot an issue. thanks for being such a welcoming community.

@droneflying thank you for being the most courteous and professional member. your responses and kindness were well appreciated. I guess that even if VPS is disables mid-flight, you might not be able to defeat the VPS altitude issue. (Or maybe i didn't fully turn it off when i tried)

jtt777 Posted at 2017-8-6 18:12
This is just downright attitude. hallmark007 is not helpful but condescending. there is no need for attitude and assumptions and people aren't being responsible and knowledgeable of what they are doing. i'm an extremely responsible flyer who's logged many miles safely and encountering peculiarities with the behaviour of a mavic pro in non GPS conditions.

what a downright hostile group. i have no need to explain any more to the bullies on this forum. i can't belive then ephentz joined in on the rant of assuming all sorts of stuff about who is writing on here and what they value. Go ahead with your blanket assumptions and feel better about yourself instead of embracing others than also enjoy this hobby.

Don't worry too much about the negative comments.

One of them made a negative comment to me as well.
Those people are thinking they are the DJI rep or Lawyer to protect the company.
Also they often start talking about the Law, manuals, conditions etc...to find your fault rather than addressing what actually happened and how to rectify.

They just want to be in higher position like "Newbie can tell me any thing and I'm always right"

Sad.
Oh, by the way, Mavic is the Toy. #18.

jtt777 Posted at 2017-8-6 14:59
I agree if no GPS you can be restricted to 16 ft but what about when i disabled VPS, why was I still restricted?

Also, i think the manual's explanation is horrible. It doesn't cover the scenario of flying down into something or off a balcony.

First off I didn't say you weren't a responsible flyer, I said take responsibility for what you done. You said you turned off VPS when you clearly didn't as shown in your log, I explained in my first post to you what  happened, if you had have disabled VPS before you started your flight then things might have been different.
Read post 13 again and you might understand what you said.