How Accurate is your minis RTH
- Thread starter Motorcycle Rider
- Start date
Bussty
Well-Known Member
Sethjamto, the height measurements are not very reliable, what you saw is not unusual. GPS height is even worse, I have seen -10s of metres below sea level when the drone was over my head and I was several metres above the sea at a beach.
The warning may have been unsuitable landing place or words to that effect. My mini doesn't like my front lawn because, I think, the grass is long and I have seen that warning if it is trying to land there.
The warning may have been unsuitable landing place or words to that effect. My mini doesn't like my front lawn because, I think, the grass is long and I have seen that warning if it is trying to land there.
DrizzyDrones
Well-Known Member
I really only let rth run briefly to get the drone pointed in the direction of home and/or to get the feed back then I shut it off and take over i of course did accursey test and the tines it was pretty spot on was when home was updaed while on the takeoff spot i find that the home point is updated a few moments after I take off i think it’s probably because alot of times in taking off my back patio and home point updates when it gets enough satellites but I wonder if people started motors and lifted and hovered right above the landing pad until the app is done and home pt updates then fly off i have found that I take off and move out a few feet and up to eye level for a quick inspection and make sure it’s stable hovering and a quick check of settings (rth altitude ect) but my home point updates then and not from the take off spot I guess if I left it sitting it would but close to house it picks up the satellites quicker when in air. Does Moving camera down make a difference? Probably not I catch almost all my landings anyway
Question for anyone with a precision landing equipped drone - does it need a landing pad, or some obvious detail for the downward facing camera to detect for it to land in exactly the same spot as takeoff? Does the precision land feature work on a featureless surface (eg smooth concrete/asphalt)? Presumably it records a picture during takeoff , and aligns itself with that for the final touchdown for landing?
DrizzyDrones
Well-Known Member
Im not sure but i Was watching the “idaho was quadcopter channel “ And he was having trouble getting the mini to do the stuff circle around a cell tower the mini would lose the targe at a certain point but i think that was a contrast issue seemed to me the at the point where the tower blended into the background color is when it would lose so based on that in sure precision landing the pad helps it lock on .. i think some drones do a scan of the landing spot on takeoff i have seen like an active track box on videos with precision land.. you have me curious now tho if u put say a quarter to mark the take if spot in a grass feild where all then same would precision land in same spot hmmm anyone ever tested?
? That’s very accurate for ‘gps only’ landing assist. You would need the camera, ‘precision landing’, to increase accuracy. (Not available on the Mini).
Public GPS is only accurate to about 3-5m so in practice it can sometimes land a few inches from take off point and others a few meters away. That’s all good. Anyway one can steer the drone while RTH landing so there should never be a situation where you’re landing on a cliff edge and it goes over ?
I've only used RTH a couple of times but each time it hit the landing pad. I was impressed!
I usually use RTH to get it quickly back to the general area and the override it to land, but when I've let it run the full RTH, it's been typically within about 3 feet (one meter) of the takeoff point. I figure that's pretty good. Never checked the altitude though, I'll try to remember that next time.
I tried it again today, even got out a tape measure this time, 4.5' off to the south west, and altitude read - 3'
But the flight data would show the drone exactly on the home point because of the variable inaccuracy of GPS.
Try it 10 times and you could get 10 different landing points around the launch point, some closer and some further away.
It's common and normal for the barometer to give slightly different height readings for the same point over the time of a flight.
Don’t forget you must be at least 20 metres away for RTH to work. If not it will just auto land wherever it is.
EyesWideShut
Well-Known Member
I agree with @Meta4 but I've seen another thread about the inaccurate altitude and/or position when landing. Not saying it was happening here, but I think it's often caused a takeoff before the home point is established giving the return landing altitude a minus number because the mini was flying or lifting off when the HP was set.
A more accurate test might be would be to reset HP while on the "landing pad" so it takes that variable out of the accuracy test when making a measurement.
It was on the landing pad when its new home point was set. I do not take off ever, until I hear it tell me its established where it is sitting, as the updated home point.
The little bugger continues every flight to impress the heck out of me. I would be impressed by a 20' miss, but the maximum so far was was about 7' to 8' off, I didn't actually measure it, just an estimate. This mini has exceeded my expectations in every way.
At first I was even concerned to fly it in any wind, because I read here that the mini can't take any wind. One day it was fairly windy, and I thought to myself, screw it, if it blows away so be, I can order another one. So I went out, set it to sport mode to give it a fighting chance, and despite numerous warnings from the drone about high winds, and to descend, and return home, I had a fun flight of almost 25 minutes. I don't worry about it too much anymore. About every 10th flight or so I just hit RTH and let it do its own thing, just to see how accurately it will return, and it is pretty close.
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It was 286 meters away when it went into RTH mode yesterday, but had flown a few kilometers total that flight, in all directions around me. It actually initiated an automatic RTH yesterday when the battery was at 25%, which I frequently cancel, and fly it home manually, I just didn't cancel yesterday was all.
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The cause is just drift of the barometer sensor.
The zero height doesn't come from GPS.
When you power up the drone, it shows the zero point immediately well before you have GPS and a home point.
Even if you wait for GPS and home point before lifting off, you'll commonly see a small difference later in the flight.
Small changes in air pressure over the duration of a flight are enough to alter the height reading be a few feet.
EyesWideShut
Well-Known Member
Thanks @Meta4 for the info that the zero point is set at power on. I wasn't aware of that. I guess you are seeing that in the data readings. I have yet to play around with them, the learning curve seems intimidatingly. Are there any video tutorials to help getting started?
I was aware that fluctuations of air pressure can cause a different reading but I thought I saw in that other thread mention of several meters below zero were being reported. That's why I thought a takeoff before HP was established was the culprit.
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