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Compass calibration on a ship...

Discussion in 'Inspire 1 Discussion' started by likeaninja, Jun 8, 2015.

  1. likeaninja

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    Hi all,

    I have seen this question come up on other forums for phantoms etc but with no real answer, however not found anything on here.

    I have a conundrum, in that I have a potential job flying from a huge steel ship to survey stuff, but I need to be able to calibrate the compass. I will be hundreds of miles offshore, without the ability to hop on a small dinghy or land to do a calibration.

    Is there a way to do it? I have thought about large poles to hold the inspire a long way up in the air, but this seems logistically tricky. The alternative is to insulate the inspire from the steel surrounding it somehow during the calibration.

    Alternatively is there another quad or flight controller out there that is capable of some sort of manual calibration?

    If anyone has any experience, or knows THE way of doing this sort of thing (if at all...) I'd be really grateful.
     
  2. The Editor

    The Editor Moderator
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    Hmmmmm...... That COULD be a tricky one.

    Firstly, there would be no way to 'insulate' yourself or the Inspire from the magnetic influence of the ship. A pole wouldn't work as with that much mass of steel you would have to be several hundred feet away to be clear of influence.
    If you calibrate (if it would even let you without an error) on deck you would be calibrating within the influence of the ships magnetic affect.
    Once you were airborne you would be clear of that and your compass would be out.
    If it was me I would calibrate on shore as near to your leaving point as possible.
    Then, do not calibrate on board. Of course, the problem will be your mod values will no doubt be way off due to the ships affect.
    That's a real tricky one I'm afraid.....
     
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  3. lake_flyer

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    There a youtube channel form a guy who flies Flame Wheels with NAZA-M or Lite from big tankers in the ocean.
    he's a nice guy and has wonderful videos taken in the middle of the ocean.

    He might offer some advice on his channel.
     
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  4. Kilrah

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    With a naza it's easy, disconnect the GPS and you're free. You then have to fly ATTI only obviously.

    Envoyé de mon SM-G920F en utilisant Tapatalk
     
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  5. lake_flyer

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    Yeah, good old Naza-M.
    I might dedicate my Phantom exclusively to this kind of purpose one day, with a different frame/shell.

    Flying in Atti around a fast moving ship, while on that ship, must be quite a challenge though, unless it moves with the wind direction/speed.
     
  6. Paul Joy

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    I would definitely only use ATTI if shooting from a moving ship as the inspire locking itself in position while it's landing spot and the huge structures around it are moving could be disastrous. You definitely don't want to use RTH either as the Inspire will make a nice gentle return to the point in the ocean where it started! Is the RTH to the controller now working?

    I would imagine taking off using P-GPS would very quickly get messy as well, although it would be interesting to know what the Inspire would do if it's GPS data told it it was moving north at 20 mph as it lifts off yet the VPS tells it an entirely different story.
     
    #6 Paul Joy, Jun 8, 2015
    Last edited: Jun 8, 2015
  7. sirnikolas

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    I reckon you possibly could if she allows you to take off in Atti. I'd keep away from GPS mode though just in case it decides to fly to the last home point :O
    Also don't cache any maps or even have wifi or data on.
     
    #7 sirnikolas, Jun 8, 2015
    Last edited: Jun 8, 2015
  8. likeaninja

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    Very interesting, and thanks for the responses.

    So am I right in thinking, so long as I only use Atti, which I do anyway when flying from smaller boats then there is no need to worry about the compass? This solves many of my problems with the jobs I tend to do anyway! A lot of it is trying to find a place in a harbour that is nowhere near metal (quite tricky and normally involves quite a hike!) so that I can calibrate before heading out on the water.
     
  9. sirnikolas

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    My only concern would be, what happens if you lose RC signal? Where is she gonna go? What will she do?
    I'd jump on Dji 24/7 tech support and ask them those very questions. And if you're happy with their answers then go nuts. But, make sure to save the convo just in case it all goes pear shaped.
     
  10. Kilrah

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    Well there still is an issue because an i1/p3 will not even let you start motors if the compass data is considered invalid, regardless of mode.



    Envoyé de mon SM-G920F en utilisant Tapatalk
     
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  11. Kilrah

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    Very simple, you lose your bird, end of story.



    Envoyé de mon SM-G920F en utilisant Tapatalk
     
  12. sirnikolas

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    I know. I just couldn't bring myself to type that.
     
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  13. likeaninja

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    Ha ha, yes well I realise it is a little experimental and unusual! I'll try it first on land etc when I am next travelling more than 100 miles or so I'll try and take off in Atti without calibrating, and see what happens. Maybe try it with the old phantom before the i1...

    My next problem is needing a longer lens on it! - I'm sure DJI will resolve that before too long though.
     
  14. The Editor

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    NOT with the extremely dynamic and rock steady 'Dynamic Homepoint' feature you won't.
    Oh no, hang on a minute, it has to be dynamic doesn't it and, er...it would have to be able to establish a reliable GPS fix so, ummm, scrap that idea.
    Yup.....it would take a swim with the fishes!
     
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  15. jon b

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    I could get my inspire to calibrate on a dock with a metal structure or on the 28 foot cuddy cabin a client wanted me to fly from. My solution was the good old Phantom V1.1.1 that was collecting dust in the closet. That flew with no issues and enabled me to hand catch in windy and choppy conditions (video here )
     
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  16. jon b

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    Oh yeah, and if you follow him, you'll hear how his custom built FPV Flamewheel was lost at sea. It happens eventually and the sea is unforgiving.
     
  17. lake_flyer

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    He lost them because of technical failures, ESC or motors. Not specifically because he was flying from the ship.
    But you're absolutely right. If something goes wrong the bird is on the bottom of the ocean. But lake, river or ocean, doesn't matter, an I1 will drown anyhow.
    The question however, was about flying from a steel vessel. Not wether is would be unsafe to fly over water. We all know that.
     
  18. Alanl33

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    Did anyone manage to resolve the compass calibration on a ship or did the calibration on shore and taking a risk work? As I'll be shooting 4 hours off shore soon as well.
     
  19. tapcon

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    I just did a shoot off a moving vessel the other day. Despite everything telling me that this was a bad idea, I couldn't help making the attempt to see if it worked. Also, I was shooting for my friend's wedding (the boat cruise was for the rehearsal dinner).

    When I initialized the I1, everything came up green. Despite all mod values were within acceptable tolerances, I decided to do a compass calibration. I double checked my mod values, and still, everything was good. I kept the I1 in P-GPS mode and decided to give it a go.

    My launch site was on the stern and we were moving at about 10 knots. Unfortunately my launch site was less than ideal, I had a flag pole directly behind me and a string of lights going from the flag pole going all the way up the center of the boat. So I had to mentally prepare myself on what I was going to do as soon as I took off. After rehearsing my stick movements, I finally started the engines and took off.

    As soon as I took off, I had to match the speed of the vessel and strafed to the side to be clear of all obstacles. The flight went fine, but unfortunately I had to cut my flight short because the mother of the groom came up to ask me to make a speech. So I brought the I1 back in for landing.

    I don't think I had ever sweated so much when flying a drone. It took every ounce of concentration to land on a moving vessel with a limited landing area. But I did it. After about a half a pack of smokes and making my speech, I went back up to re-launch so I could get the rest of the footage that I wanted, but unfortunately there were too many people up on the deck to allow me to take off and land safely.

    Anyway...bottom line, it can be done. Here is the raw footage:

     
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  20. damoncooper

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    Nice. Looked like that captain was about to have a meltdown :)

    That line overhead was a concern as well.

    But well done!