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RTH accuracy

DJI replaced my Mavic air 2 drone as a repair or replace agreement.

In flying the replacement unit the "RTH" return spot misses the take off spot by around 10 feet ... (varies)

not good as it landed on the side of the deck and fell to the ground .. (deck is 16' wide and took off in the middle)

seems to be no damage this time but how can I fix this?
 
Only ever landed using RTH to see if it worked and it landed on my pad but that was a M2P, 10 feet is a fair way out.
Now on the rare occasion I use RTH (usually if I look down at my screen then back to the drone only to realise I lost track of it.) when I spot it again I cancel & land manually so have no idea how accurate is expected.
 
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On take off did you go straight up to 7m+ ? I have to ask were you not watching where it was coming down?

I might not have gone straight up to 7m but I'll try that thanks

I watched it land but it was just over the center of gravity and went over...I thought it would land on the edge of the deck ok ... sort of panicked should have cancelled rth but didn't
 
It would perhaps be interesting to post the txt and DAT flight logs and let one of the gurus compare takeoff point, homepoint and landing sight coordinates etc.
 
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RTH accuracy

DJI replaced my Mavic air 2 drone as a repair or replace agreement.

In flying the replacement unit the "RTH" return spot misses the take off spot by around 10 feet ... (varies)

not good as it landed on the side of the deck and fell to the ground .. (deck is 16' wide and took off in the middle)

seems to be no damage this time but how can I fix this?
There are many factors involved with the landing spot:
  • If the MA2 has enough data and telemetry to perform a precision landing, then it should come very close to the original takeoff point. If however it does not have that data, it will land based solely on GPS positioning. Although 10 feet is a bit far, that is well within the range of expected GPS precision.
  • In order for precision landing to perform properly, a lot of things need to happen:
    • You must have a home point established prior to takeoff.
    • You must climb straight up to around 20-25 feet without any lateral movement.
    • You must not give any lateral stick commands during the landing phase. Doing so will turn off precision landing from that point on.
    • You must have sufficient lighting, both during takeoff and landing.
    • The ground conditions should not substantially change between takeoff and landing.
    • The takeoff/landing spot must have good definition in contrast to the surroundings. If you are taking off from a uniform surface (like a concrete slab, blacktop, or perhaps a deck), then precision landing will not work well.
As already mentioned by @THE CYBORG it has its place and it is always good to know how it works (as with all of the drone functions), but learning to navigate and operate the drone manually through all phases of flight makes you a better pilot overall. Landing manually means you have positive control at all times and are better prepared to handle any issues or emergencies.
 
With an android phone connected to a windows computer via USB :-

1) for the txt flight logs look in the folder
Computer/phone's-name/Phone/DJI/dji.go.V5/FLightRecord

2) for the DAT flight logs look in the folder
Computer/phone's-name/Phone/DJI/dji.go.V5/FLightRecord/MCDatFlightRecords

For a set up using something by Apple you have to use iTunes but the locations are from memory the same.

You might like to look at DJI Flight Log Viewer | Phantom Help
 
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RTH accuracy
In flying the replacement unit the "RTH" return spot misses the take off spot by around 10 feet ... (varies)
not good as it landed on the side of the deck and fell to the ground .. (deck is 16' wide and took off in the middle)
seems to be no damage this time but how can I fix this?
There's probably nothing to fix.
Consumer GPS is not pinpoint accurate and can often be +/- 6 feet (or even more), so that is completely normal.
Obstacles blocking part of the skyview might reduce GPS accuracy even further.
Your drone can use GPS alone to give approximate RTH landing accuracy.
Or it has a Precision Landing feature that uses optical technology to give RTH landing accuracy within inches.
Look for Precision Landing in your manual to learn how that works.

Knowing that the RTH autoland feature might not land precisely on the launch point, if you allow RTH to land your drone, you need to have a clear area around it to allow for the approximate nature of autolanding accuracy.

You mention the drone landing close to the edge of a deck.
Where something like this is possible you should not be allowing the drone to autoland.
You should be landing it yourself where obstacles or unsafe landing issues are close to the landing spot.
 
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Interesting, I should have read the manual more thoroughly. I overlooked the “precision landing” section. That looks cool. I am someone who rarely uses RTH but now knowing that it uses a snapshot of the take off terrain. I will now keep that one in the bank.

Looks like I’ll go up 7m at the start of every flight. Seems that’s the key!

I could see that precision landing coming in handy let’s say if you a unforeseen incident. Having confidence that it can land with a better accuracy then standard GPS error is fantastic. Also makes those launching pads more resourceful.

Great post, when first saw it my initial response was, “you can’t expect pinpoint accuracy with GPS” it’s not perfect! But alas. A clever little trick, I”m going to test that tomorrow morning. Thanks.
 
RTH accuracy

DJI replaced my Mavic air 2 drone as a repair or replace agreement.

In flying the replacement unit the "RTH" return spot misses the take off spot by around 10 feet ... (varies)

not good as it landed on the side of the deck and fell to the ground .. (deck is 16' wide and took off in the middle)

seems to be no damage this time but how can I fix this?
Set F1 to camera down, monitor the RTH landing and if it drifts, land manually from about 10’ up. Switching to Tripod Mode helps. Also follow the recommended take off procedures: I use Tripod Mode if a bit windy, F1 camera down after launch, pause at about 15’ AGL before flying off, to let the drone capture a good landing zone image - and use an “H” marked folding landing pad. RTH often returns within the pad for me, especially with good GPS fixes and bright light at the landing area.
 
watching this video Flytpath precision landing

first 2 experiments had a 2m and 2.5m error in landing. The last one with a small landing pad was only say 10-15cm. it seems having a well defined landing point with clear contrasts really helps the precision landing feature.
 
watching this video Flytpath precision landing

first 2 experiments had a 2m and 2.5m error in landing. The last one with a small landing pad was only say 10-15cm. it seems having a well defined landing point with clear contrasts really helps the precision landing feature.
If the drone landed 2 metres away, it wasn't using the Precision Landing feature.
And if you look at the surface it's no mystery why Precision landing couldn't work.
The uniform green surface has no distinctive features for the Precision Landing system to identify and match.
The mat is completely unnecessary as long as the home point terrain features are sufficiently distinctive and well lit.
 
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I have done a precision landing with an M2P and it was inch perfect. However it does need an reasonable empty space around the landing site to do this. The intial positioning, at the start of the descent, may not be 'accurate', in my case it visibly adjusted its position as it descended and presumably came within range of the downward looking sensors.
I can not use it if I fly from my front garden as the 'error' in the initial positioning often means the descent path would bring it down in trees.
 
I might not have gone straight up to 7m but I'll try that thanks

I watched it land but it was just over the center of gravity and went over...I thought it would land on the edge of the deck ok ... sort of panicked should have cancelled rth but didn't
You have to go up to 7meters or it will never work.
 
Never use RTH, aways bring it home manually, have battery set at 30% warning and at 10% critical battery warning. By that time its sitting on the landing Pad.
 

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