Are landing mats causing a problem with drone compass calibration?

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I don't think that this issue has been raised before, but apologies if I am repeating a topic..

The landing mat I use, like most on the market is the 'pop up' type that has a steel band around the rim. That got me thinking about the interference with the drone's compass from this large steel ring! I tested it with a hand-held compass, and it clearly deflects the needle when I move it over the rim.

Could landing mats be causing unexplained crashes without us ever suspecting the real culprit?
 

Meta4

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Could landing mats be causing unexplained crashes without us ever suspecting the real culprit?
What unexplained crashes? .. (there aren't many)
What is the diameter of the mats? .. (this will give an idea how far the compass sensor is from the steel ring.
How thick is the wire?

I wonder if the effect might not be a worry because the steel is too small and too far from the compass sensor and with a uniform circle around the Phantom, there won't be an unbalanced effect in any one direction.
The thing to do to check, would be to place that hand compass in the centre and see if it is deflected.
 
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sorry about the piggyback Julez, but was wondering if Meta4 could answer this one. Since these compasses are electronic, does a close by magnet effect the compass only when its powered up or also when unpowered ? Thanx !
 

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sorry about the piggyback Julez, but was wondering if Meta4 could answer this one. Since these compasses are electronic, does a close by magnet effect the compass only when its powered up or also when unpowered ? Thanx !
Sorry ... I don't know and don't like to guess.
 

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Magnet sticks to mine. Surprised, though it would be nonferrous. Never caused a problem but I will try a compass to confirm. Nasty trick to magnetize someone’s landing pad. 😫
 
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Cost on the landing mat may be part of the magnetic ring component.
Doubtful that the manufacturers would use stainless steel because of the added cost. This pad works well for me and you could add several pieces to make it larger. Easy to cart around. Two foot square.
4040C181-8002-4CF2-B560-07A9A65BE54B.jpeg
 
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Hey Starz, give that “landing mat” back to the kids.😂
 
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My mat is just over 1m in diameter and the steel ring is 5mm deep. It clearly affects a compass as you approach the ring area, but has little deflection in the centre. It makes me think that if you take off or land anyway but vertical, the IMU will suddenly disagree with the drone's compasses. This is a known factor in drone mishaps.
 
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I don't think that this issue has been raised before, but apologies if I am repeating a topic..

The landing mat I use, like most on the market is the 'pop up' type that has a steel band around the rim. That got me thinking about the interference with the drone's compass from this large steel ring! I tested it with a hand-held compass, and it clearly deflects the needle when I move it over the rim.

Could landing mats be causing unexplained crashes without us ever suspecting the real culprit?
I believe that you may well be on to a potential problem with these mats. I have previously described on this forum a similar problem that I encountered with magnetic interference in the backpack from which I launch my P4. The problem I had was totally my own fault but it nearly cost me my bird. I wore shooting gloves, that have tiny magnets sewn into the fabric, to the launch site which I then took off and put into the backpack from which I launched. The drone behaved oddly as I turned onto a bearing it rotated past the bearing and when I returned it onto the desired bearing it rotated fractionally past again. When I engaged Course Lock it flew off. I did get the P4 back and found the problem gloves. I also found that a folding tablet screen sun visor that I had in the backpack also had soft 'fridge door' type magnets built into it to clip the folding visor together. This screen visor was sold specifically for use by drone pilots!

When I investigated the above problem I could see the compass error increase as I moved the P4 towards the backpack. I would therefore suggest that you open the compass calibration screen in the DJI Go4 app and watch to see if the error increases as you move the drone over the rim and into the centre of the mat.

I would also suggest binning the mat.

All the best, Martin
 
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hadn't thought of this. I love my 5 ft diam. with heavy steel cable pad that lets me fly from sage brush and hay fields..........and haven't had any problems....
 
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You know those sample carpets (~ 18" X 24") at Home Depot they let you take home to dwell on buying? Those carpet samples get thrown away all the time because carpets will go EOL. Those sample carpets are perfect launch pads, just a bit more bulky. Throwing one in the trunk of your car can be useful for other purposes too, like kneeling down on concrete to inspect something on the car, or to stand on dirt/sand while changing your shoes, etc. Carpet stores throw them away all the time. They have no ferrous metal either.
 
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I can't speak on whether or not the metal ring in your mat is actually affecting the compass or not but it's not something I use Nor would I ever use it. I use a custom made (homemade) wooden landing pad that raises the aircraft about 3 inches of any surface and so far I've never had a compass error.
 
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I use one of those circular pop-up mats too and never had a problem. A solid, non folding mat would not work for me as I often hike or bike to my launch site.

Chris
 
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This is my homemade landing pad: A bath mat, a bin lid, and six velcro strips. Non-ferrous, highly wind resistant, and always a plush, soft landing. (BTW check for nickel - it’s the other common magnetic metal).

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I feel better now, no wonder I could never land the drone back on the mat.
 
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Been reading through the above comments as I have one of the circular "folding" landing mats. I can quite understand how all of the problems arise.

My mat has 4 fabric loops and was provided with four plastic pegs with which to peg it down. I don't often use them as the mat is fairly stable at ground level on smooth, level ground, but now I'm contemplating removing the metal ring and always using the pegs to stabilise the mat.
 
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Mine had to improvise a piece of soft tile, worked like a charm and then modded the drone to increase clearance to gimbal using legs from the Phantom 3
 

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