Very poor night flight ! ?

[ScumFrog]

Hi guys , this is my second MM.
the first MM flys perfectly at night with poor lighting ! well not as during the day , but it flies and it hovers rock solid.

i also bought a second hand MM today , which is totally the opposite , it fly pretty bad in poor light and zero wind !
by bad i mean too bad that i cannot control it and sometimes it does not respond to stick inputs ! its twitchy and even landing it is very difficult , although at day its rock solid !

i tested it also indoors with good lighting its also rock solid !

what could cause this ?
outdoor flights , 7-9 sats , latest Firmware . iphone xs .

 

[lannes]

Probably not enough satellites, being at night vps would have turned off

 

[Juggler]

not sure about the sats>>
sats is for position to my understanding, the RC transfers data to the screen direct from drone not via sats. Sounds to me like a light sensor issue

 

[DougMcC]

not sure about the sats>>
sats is for position to my understanding, the RC transfers data to the screen direct from drone not via sats. Sounds to me like a light sensor issue

My Mavi Mini must see 12 sats before I lift off. That will take sometimes a minute or more. They are crucial for stability by GPS and are not part of communications as mentioned. I would not launch a MM early while it just had 8 or 9 sats. You might try to start both MM in same spot to see if one locks on to more Sats quickly compared to the other. Maybe one GPS receiver is comprised?

 

[boblui]

7-9 satellites is insufficient. Anyway, you can post the flight logs ( .TXT and .DAT files in the phone ) if you want a deeper investigation . Check this to get the files : Mavic Flight Log Retrieval and Analysis Guide

 

[Juggler]

Sorry I misread the OP as very poor night fliming...dont know what my brain was seeing...henc my previous post

 

[ScumFrog]

well i dont think its sats , because even indoors with zero sats , i could hover pretty good with good lighting !
but outdoors with low light , its very very scary !!
so what about this light sensor !! could i replace it or clean it ? im technically oriented so i could do it myself !

 

[lannes]

well i dont think its sats , because even indoors with zero sats , i could hover pretty good with good lighting !
but outdoors with low light , its very very scary !!
so what about this light sensor !! could i replace it or clean it ? im technically oriented so i could do it myself !

The fact you could hover indoor with no sats, means that there was enough light for the VPS to be active.
Outdoors with no light means the VPS would be inactive, when the VPS is inactive it's the GPS that holds it in place.
If there is not enough sats for a good fix then the positioning would be affected, are there tall buildings around that could affect the GPS signal ?

 

[ScumFrog]

The fact you could hover indoor with no sats, means that there was enough light for the VPS to be active.
Outdoors with no light means the VPS would be inactive, when the VPS is inactive it's the GPS that holds it in place.
If there is not enough sats for a good fix then the positioning would be affected, are there tall buildings around that could affect the GPS signal ?

yes i have sky scrappers around me ! all around ! thats why i cant lock to more than 8 stats !
so what ur saying , is i am flying outdoors at night with no VPS and NO GPS ! just the Gyro !

 

[Deleted member 103366]

Try adding a screen video recorder to your phone.
In a situation were you REALLY want to concentrate on watching the actual drone they are VERY handy for later 'analysis' e.g. checking the number of satellite links.
I use Xrecorder but there are others out there.

Insufficient satellites and no VPS = ATTI mode = no position holding and at the mercy of the slightest breeze unless countered by the pilot..

 

[ScumFrog]

Try adding a screen video recorder to your phone.
In a situation were you REALLY want to concentrate on watching the actual drone they are VERY handy for later 'analysis' e.g. checking the number of satellite links.
I use Xrecorder but there are others out there.

Insufficient satellites and no VPS = ATTI mode = no position holding and at the mercy of the slightest breeze unless countered by the pilot..

will do that...

in my case , there was zero wind , but the drone kept doing sudden movments without any stick input from me , so i had to compensate that with stick movments .
movments were random , so not in only one directly , in all directions.. ill try to make a video . its hard to explain

 

[Deleted member 103366]

Sounds like it is in ATTI mode, you could get that confirmed, or not, using the flight logs as suggested by Boblui in post #5.
I too suggest reading the relevant bits in the 1st post of
Mavic Flight Log Retrieval and Analysis Guide
and then either uploading the txt file to
DJI Flight Log Viewer | Phantom Help
or to here posting, then some of the folks in here can do their stuff.
If trying to shoot a video of it switch to FPV mode, that way sideway tilt will show up.

 

[EyesWideShut]

will do that...

in my case , there was zero wind , but the drone kept doing sudden movments without any stick input from me , so i had to compensate that with stick movments .
movments were random , so not in only one directly , in all directions.. ill try to make a video . its hard to explain

It's not hard to fly the mini when it's in "ATTI" mode, just be gentle on the controls. Usually the AC stops on a dime when the sticks are released due to the GPS and bottom VPS sensors. When a stick is released in ATTI, the mini will continue to drift in the last direction unless an opposite stick command is given to neutralize the drift.

Problems might occur if the VPS and/or GPS starts up again, maybe by being higher and getting more satellites and you don't realize it or hear it. If you know it might happen you'll understand what's happening and be able to adjust back to regular stick operation.

You can have fun practicing ATTI flying indoors if you put a wide elastic band around the mini's bottom sensors (or tape) if you also have no GPS lock. Tinfoil over the top of the mini's back might help lower the GPS strength if needed.