Hi. Today I put on a ND filter on my Mavic Air 2 for the first time and flew it. It was the first time I ever had an inaccurate RTH landing ( it was going to land about 5 ft. off). I was wondering if because I didn't calibrate the gimbal it threw off the landing (for what reason I don't know). Anyway I went home and calibrated the gimbal and then flew again. RTH was perfect. I checked GPS satellite history in AirData and I actually had more satellites the first flight. Horizon in the video of first flight looked good. Wind was variable for both flights.
I would like to know if there is a logical explanation why an uncalibrated newly ND filtered Gimbal might throw off the accuracy of the RTH or was this experience just a coincidence? Thanks to those who read this and more thanks to those that can help me.

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I think the most important thing for an on target landing is the 7 meter straight up takeoff. I go to 8 meters and hold for five seconds before any maneuvering. Then, when the drone starts to descend on the RTH, I see the visual system precision landing take over about 7 meters up and minor directional inputs are made. This corrects for any minor GPS errors.  You can help by taking off from an area that has distinctive visual characteristics whether it’s a landing pad or ground color feature...like at the park where a dog peed and there’s a one foot circle of yellow grass...wink wink!!!

Rustic17 Posted at 6-21 18:07
I think the most important thing for an on target landing is the 7 meter straight up takeoff. I go to 8 meters and hold for five seconds before any maneuvering. Then, when the drone starts to descend, I see the visual system precision landing take over and minor directional inputs are made. This corrects for any minor GPS errors.  You can help by taking off from an area that has distinctive visual characteristics whether it’s a landing pad or ground color feature...like at the park where a dog peed and there’s a one foot circle of yellow grass...wink wink!!!

Hi. Yes I have a landing mat which I use and I am in the habit of hovering at about 25 ft upon takeoff to let the drone take a picture of the landing area. Maybe I didn't hover in the first flight but the video shows I did. Possibly I didn't take the drone straight up and that caused the inaccurate landing - I'll have to look at the video but I'm thinking I didn't start the video right at takeoff. I am always so excited to fly this drone that sometimes I get anxious and rush into the flight.

Don't we all (get excited)...can't remember the number of times I've forgotten to check that the home point was updated or turned on the recording.

Rustic17 Posted at 6-21 18:20
Don't we all (get excited)...can't remember the number of times I've forgotten to check that the home point was updated or turned on the recording.

Hi Rustic. You know I don't remember hearing my lady friend in the controller say " The home point has been updated" on the first flight. Do you know if it is possible to confirm whether or not the home point was updated for a particular flight?

It was the first time I ever had an inaccurate RTH landing ( it was going to land about 5 ft. off).

I would like to know if there is a logical explanation why an uncalibrated newly ND filtered Gimbal might throw off the accuracy of the RTH or was this experience just a coincidence?
It had nothing to do with your gimbal etc.
If the RTH autoland was 5 ft off, it was not using or not able to use the Precision Landing feature and used GPS only.
GPS is not pinpoint accurate and will usually put the drone within 6 feet or so most of the time and sometimes even further off.

Precision Landing uses optical technology and would not be affected by the filter or calibrating anything.
I don't remember hearing my lady friend in the controller say " The home point has been updated" on the first flight. Do you know if it is possible to confirm whether or not the home point was updated for a particular flight?
Yes, it's possible to confirm by examining your flight data.
But in the case you described, your drone obviously recorded a home point very close to where the drone landed.
+/- 5 feet is perfectly normal when you only have GPS for RTH autoland guidance.

Magicdroner Posted at 6-21 18:25
Hi Rustic. You know I don't remember hearing my lady friend in the controller say " The home point has been updated" on the first flight. Do you know if it is possible to confirm whether or not the home point was updated for a particular flight?

As you power up the drone, watch the number of satellites and around 9 you will see a Home Point message on the left side of the app.

I'm not sure if this makes that much difference but my RTH landings have all been within the 36" landing pad. Were you using a pad? I suspect that it is easier for the drone to match a unique high-contrast image like that.

Sorry, I see you are using the pad...

I am usually within 3"...but again, I don't think it's the GPS that's making for the accurate landing...I think it's the precision landing feature that makes it so accurate.  When I don't use the landing pad I'm closer to 36".

Rustic17 Posted at 6-21 21:48
I am usually within 3"...but again, I don't think it's the GPS that's making for the accurate landing...I think it's the precision landing feature that makes it so accurate.  When I don't use the landing pad I'm closer to 36".

Hi. I checked my AirData flight data and have attached a screenshot of the notifications I got on the second flight (which had a perfect RTH). It gave me a vision sensor blocked prompt right when I started the drone and it was sitting on the landing pad.
Maybe this is why the first flight had an inaccurate RTH landing (there was no vision sensor blocked prompt on the first flight however). Precision landing was enabled on both flights I'm pretty sure because I didn't change any settings and I've always had it on.

By the way the drone landed on the two flights you'd think I would have had a vision sensor blocked prompt somewhere on the first flight and not on the second flight instead of vice-versa. Kind of strange. I'll keep monitoring these behaviors. Sorry for the redundant screenshot.

Magicdroner Posted at 6-21 22:19
Hi. I checked my AirData flight data and have attached a screenshot of the notifications I got on the second flight (which had a perfect RTH). It gave me a vision sensor blocked prompt right when I started the drone and it was sitting on the landing pad. [view_image]
Maybe this is why the first flight had an inaccurate RTH landing (there was no vision sensor blocked prompt on the first flight however). Precision landing was enabled on both flights I'm pretty sure because I didn't change any settings and I've always had it on.

Precision landing was enabled on both flights I'm pretty sure because I didn't change any settings and I've always had it on.
You can have Precision Landing enabled, but that doesn't mean it will work.
The manual gives a list of situations when Precision Landing will have difficulty.

A J Posted at 6-21 23:06
[view_image]

Thanks for that info. I flew today with no problems and had another precise landing. I have attached a 12 MP photo unedited from that flight.  12 MP Photo

Magicdroner Posted at 6-22 17:25
Thanks for that info. I flew today with no problems and had another precise landing. I have attached a 12 MP photo unedited from that flight.  12 MP Photo

Nice looking golf course!

Magicdroner Posted at 6-22 17:25
Thanks for that info. I flew today with no problems and had another precise landing. I have attached a 12 MP photo unedited from that flight.  12 MP Photo

Hi. I am sorry to know about your previous trouble and I am happy to know that your previous trouble was resolved. If you have further concern or inquiry, please feel free to post it here at DJI Forum, we are here to help. Thank you for your valued support.

I had some experiences with this today. Because of this discussion, I was committed to limit my lift off to about 8 meters as recommended. Well, that did not go as well as before when I was going straight up about 20 meters. I had to cancel RTH and land manually three times in a row. I wondered why. So I went back to using my 20 meter height and the RTH accuracy went back to excellent using the same location. I thought about this for a while and realized that the main objects in the way were the tall trees and they were at least 12 meters high. So apparently the drone needs a good photo of the objects in the way to succeed and that would depend on the environment, not just a one-size-fits-all height.