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Landing

mfarris2

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Went out to fly yesterday. I took my Mavic up to about 125 feet and proceeded forward over some trees, then over a body of water. In the middle of this body of water was an island. I wanted to get down lower to take a closer look at this island so was using my left controller to lower the drone. After holding down for about 10 seconds, the controller started saying "landing." This confused me (easily done as I get older) so I pulled back up.
I tried several more times and it seemed each time I tried to lower the drone over the island,...I got the same statement from the controller. In this instance,...does the fact I am simply lowering the drone get this "landing" comment from the controller? Or was it actually going into auto landing?
I brought the drone overhead and started to lower the drone and did not get the same "landing" comment from the controller.
Thanks for your time and responses.
 
I believe this behavior comes from pulling the left stick all of the way down for a short period of time. Try practicing your descents by pulling the stick most of the way down, without pegging it all of the way down.
 
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No. That's not normal. You should upload your log file so folks here can look at it and tell you what was going wrong. May be a VPS problem since you were over water.
 
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If you were over the water it's probably the VPS problem that almost everyone experiences.

Rob
 
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Thanks everyone,...I did try pulling the stick partially down and got the same response from the controller. I was pretty high up over water to get that kind of reply I would of thought. (About 120 ft)
If someone could tell me how to put my logs on this forum I would be happy to do that. All the help I can get is much appreciated. (I am sure this will not be the last time I need to upload my logs.)
Thanks again to everyone and their suggestions.
 
When flying over water again next time, check out the VPS altitude displayed at the bottom of DJI GO to see if it's displaying a bogus value.

VPS.jpg

If you move the left stick (throttle) to the full down position when it's showing 0.5 meters (or below), your Mavic will switch to Forced Landing mode and start landing (regardless of the altitude estimated by the IMU). If you notice the VPS altitude is not accurate, it would be best to turn off the downward sensors (or never descend at full throttle).
 
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I have flown over the ocean a LOT and although I've gotten bogus elevation numbers, I've never had the autolanding kick in and I've definitely done full throttle down many times. I'm guessing there is at least one other variable involved with this behavior. But now I'm paranoid so I will probably switch off the VPS from now on. Maybe I'll test over my pool, but obviously a world of difference between a static body of water and the Pacific Ocean.
 
Hey guys. Don't know if this thread is dead, but I'm wondering if folks are getting confused between the visual positioning system and the ultrasonic. The VPS should not be returning elevation values. That "should" be the ultrasonic. In this instance, he said he was at 120 feet. Even with wonky numbers, I highly doubt his system was reporting that he was below 20 feet (when autolanding can kick in.)
 
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Even with wonky numbers, I highly doubt his system was reporting that he was below 20 feet (when autolanding can kick in.)
It's a common problem. We could confirm if the OP uploads his TXT flight log.
 
It's a common problem. We could confirm if the OP uploads his TXT flight log.
Right. And I'd LOVE your explanation of how the Mavic uses the visual vs. ultrasonic sensors. I would assume the visual is being used to maintain stationary position at low altitudes and with no GPS and to "memorize" the landing zone. While it "could" be used for elevation, I don't see why it would when there are ultasonic sensors. I'm thinking the elevation being reported on the app as "VPS" is actually utilizing the ultrasonic sensors for that. I could test it but figured you probably know the answer.
 
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I just tested autolanding behavior over and over again. Even at just a few inches remaining, the Mavic instantly kicks out of the autolanding protocol when you go full stick up. Therefore, I think something else is going on in these autolanding situations.
 
Guys,...I'm fairly new to drone flying. If someone could kind of give me instructions to getting my flight logs and uploading them here,....I would be happy to do so. I kind of want to solve this problem so it does not happen again. Thanks for your instructions and input.
 
I'd LOVE your explanation of how the Mavic uses the visual vs. ultrasonic sensors
I've never seen DJI explain this anywhere.
 
I've never seen DJI explain this anywhere.
Oh, good. I thought I was missing something. I'm pretty sure my outline above is close to correct. That's probably why there is such a big range for when the "VPS" is employed. It depends on whether it is the visual vs. ultrasonic sensor and they are grouping them together when describing. They probably are employing trade secret IP so don't want to be too specific in delineating them.
 
OK Guys and Gals,....I am new to this and just learned how to get to my logs and flight records. I'm still trying to figure out how to get them uploaded to this site. From my iPad Mini,....I have flight records in a .txt file format.
As the instruction video showed myself, I uploaded these files to Healthy Drones. However I could only bring those back as a .csv or .kml file.
Those could not be uploaded onto this forum. So all I could do was upload the text files.
Again,.....thanks for all your help.
Sorry it took so long to get these posted,...(if they even help) I had a difficult time figuring all of this out.
 

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Which log is the flight you're describing in your first post above?
 
I just tested autolanding behavior over and over again. Even at just a few inches remaining, the Mavic instantly kicks out of the autolanding protocol when you go full stick up. Therefore, I think something else is going on in these autolanding situations.
I tried this test a couple of days ago and got a different result. Starting at about 10 feet did a full back throttle and the Mavic descends to 1.6 feet when it switches to the FORCE_LANDING state. After that full throttle up has no effect; it remains in the FORCE_LANDING state, descends and lands regardless of throttle.
 
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