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Other The Quadcopter/Drone/Multirotor Thread

Discussion in 'General' started by Byron C, 4 Mar 2017.

  1. [ZiiP] NaloaC

    [ZiiP] NaloaC Well-Known Member

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    I use the drone for surveying areas of land that we're going to be using for the construction of "Integrated Constructed Wetlands" for wastewater treatment.


    So, I take whatever drone (previously a Mavic Pro, now a Phantom 4 RTK+D-RTK2), plan out a mission using Pix4D Mapper, then it flies an autonomous mission in a grid pattern. Each photo has georeference data relating to it, which also includes camera angle and other bits of info. Then I put them all into Pix4D and put it through 3 phases of processing (initialisation, Point Cloud generation, DSM rendering).

    From the Pix4D processing, I get a fully 3D model of the site, contour lines (for use by our CAD technician for design drawings) and a few other bits.

    The Mavic Pro was great for quickly surveying sites where I just needed to get a rough (+/- a few metres) layout of a site for design and planning, but the RTK unit can get me down to ~3-5cm accuracy in all 3 axis. There's a little bit of throw, since I have to convert everything to bloody Irish Transverse Mercator instead of GPS positioning, but it's not too bad. The main issue is elevation. GPS will log it at X, but ITM is usually ~56m below that value.

    The software does an awesome job of taking each of the photos, relative to its position in the grid that it flew, cross-referencing each image against others and finding keypoints in each photo. From this, the algorithms will use these key points to generate a 3D frame, then flesh it out with a point cloud to fill out the rest, then create a texture, DSM/DTM (digital terrain map - terrain without vegetation) and contours at whatever interval I want.

    What I surveyed in an hour of flight-time would have taken someone 1-2 days to do by hand, easily. The only shortfall I have, is that the software for the D-RTK2 base station does not allow for it to act as a mobile rover yet. Thankfully, for this particular site, I had an old survey of a yard that is part of the survey area, from which I got accurate and meaningful elevation data for 5 of my 7 control points (markers laid out on the ground by me), which in turn gave me a correction value to adjust the other 2 with confidence.

    All in all, I think I managed to get this down to 3cm accuracy, and this is only for machine work in a field, so that's an order of magnitude more than I needed. :D
     
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  2. David

    David Take my advice — I’m not using it.

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    A flying theodolite, but significantly more advanced. Very cool.

    I used to survey rock faces with a laser to create a 3D model for blast design - purely a safety measure to ensure explosives were not placed too close to the face prior to drilling and blasting, to eliminate flyrock incidents (sending a chunk of rock on a ballistic trajectory towards roads/public areas etc..) - it used to take forever and I can see your work as a viable application for that.

    Thanks for taking the time to explain. :)
     
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  3. Byron C

    Byron C No liability accepted as a result of this post

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    So... I'm getting rid of my drone projects :(. I just don't have the time or patience for all the tinkering and building any more; I need to just get a Mavic or similar that I can just get in the air quickly without having to spend hours tinkering with calibration & settings. Thread in the for sale section here if you're interested - includes frame, motors, ESCs, TX/RX, LiPo charger, gimbal, etc...

    That sounds very complicated but very cool...

    Surveying rock faces to create 3D models for blast design also sounds very complicated but very cool!
     
  4. [ZiiP] NaloaC

    [ZiiP] NaloaC Well-Known Member

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    I did get the opportunity to record a blasting in a quarry a couple of years ago with the Mavic.

    I would ask those who watch this to NOT share it around please, thank you.

     
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  5. David

    David Take my advice — I’m not using it.

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    It does look better on an overcast day, when you can see the NONEL flashtube initiating the dets like that.

    We used to drop about 20,000 tonnes of rock with four tonnes of explosives. About once a month we'd get a school visit - all the kids stood at the other side of the quarry - "where should I be looking, I don't want to miss it". Don't worry, you won't. Then "crump" - three days of surveying, planning, drilling and charging all over in three seconds, and they're like "oh wow, do it again". :lol:
     
    Last edited: 15 Sep 2019
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  6. David

    David Take my advice — I’m not using it.

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    Well, I didn't crash it!

    I used up all three batteries, which meant a little over an hour. Didn't use any of the advanced modes like follow, orbit, selfie gestures etc.. I just concentrated on flying around and getting a feel for the controls. Landing/taking off manually, shhoting video and stills, testing RTH and generally playing around. The fact of having something simply capable af holding it's altitude absolutely transforms drone flying.

    Sport mode is scary fun - you can buzz around at 30-40mph, ten feet off the ground.
     
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  7. Byron C

    Byron C No liability accepted as a result of this post

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    Not crashing is always a good first step :grin:.

    I briefly flew a mate's Mavic a couple of months ago, and it's in a different league compared to the flight controller I was using...
     
  8. David

    David Take my advice — I’m not using it.

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    The practise drone will be going back, if it ever arrives. It's well beyond the 4-9 shipping days promised at checkout - so maybe I can use that. If not, I'll flog it and take the hit.
     
  9. David

    David Take my advice — I’m not using it.

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    The practise drone turned up, very late. The Banggood seller wasn't interested - sorry it's late but we wont accept a return for that. Tw@t.

    Rather than piss around, I chucked it on ebay and made a healthy profit - I listed it high as a "buy it now" with offers accepted in the hope I could take a reduced offer but still get my money back, but somebody bought it outright. It isn't readily available in the UK yet, so he was obviously willing to pay over the odds to get his hands on it fast.
     
    Last edited: 6 Oct 2019
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  10. Byron C

    Byron C No liability accepted as a result of this post

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    What was the practise drone you bought? I'm sure you posted in the purchases thread, but it'll be long buried by now...
     
  11. David

    David Take my advice — I’m not using it.

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    It was an Eachine E520S with 4K camera, 5G wifi, GPS and three batteries. Budget Mavic clone.

    [​IMG]

    Amazon have it for silly money - I paid about £87 shipped
     
  12. Arboreal

    Arboreal Well-Known Member

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    I had a go at flying a Mavic Pro Platinum today, what a bit of kit!
    I've only played with painfully unstable cheap indoor drones, and it put me off.
    This was amazing.
    The guy flying it came to my work as he needed to photograph a site nearby, and I could provide a private safe location to fly from.
    I should have a memory stick in a couple of days of aerials of my workplace and the neighbouring buildings.
    Apparently, he's coming back for another go, as he didn't quite get all he needed today.
    I was seriously impressed about its stability, ease of use and the reduced noise and lower pitch on the Platinum.
    Much less intrusive than anything else I've heard.
    I'll post some images when they get in.
    Off to find elderly relatives/spare body parts to sell to fund an expensive potential new habit....
     
  13. David

    David Take my advice — I’m not using it.

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    I love my Mavic Pro, and I've only just scratched the surface. I'm currently learning Divinci Resolve to process and cut up video - it's early days but I'm having fun.
     
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