MOVI5 position recording

Discussion in 'MōVI M5' started by Fulvio Tonon, Nov 10, 2013.

  1. Fulvio Tonon

    Fulvio Tonon New Member

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    Good Day ALL!

    In the MOVI brochure, I read of a property that is of interest to me:

    The MōVI can record the following parameters:

    Pan, Tilt and Roll Angle

    Height

    GPS Position

    Velocity (both vertical and topographical)

    Acceleration

    Temperature

    Questions:

    • Can the MOVI5 record the above, and can the MOVI5 be mounted on the HL frame?
    • Which constellations are tracked (GPS L1, GPS L2, GPS L5, GLONASS...)?
    • What is the accuracy of the height and "GPS position"?
    • Can the system handle differential GNSS, where the MOVI5 is a rover? If so, how does it communicate with a base?
    • Pan, tilt, and roll angles are measured from: North, horizontal, and horizontal, respectively?
    • Where are the "GPS position" and height measured (e.g., intersection of pan, tilt and roll axes)?
    • Can the angles above be seen from the ground at flight time?
    • If the answer to the above question is NO, I need to fix the pan movement of the MOVI5 and yaw the craft so I know the camera heading. Can I fix the pan movement in the MOVI5 and just use it as a 2-way gimbal?
    • In my applications, the camera focal point (not the center of gravity) of the camera (Canon D5 MarkII + 24 or 50 mm lens) must be fixed (with respect to the craft) when the MOVI tilts and rolls the camera to stabilize it. Is it possible to do that or is it too taxing on the MOVI5?
    Thanks!!
    Fulvio
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Fulvio that functionality hasn't been implemented yet. You didn't mention indoors or outdoors. Indoors may work but you understand that GPS mat or may not work indoors.

    I'll see if I can get an update.
     
  3. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Fulvio:
    Thanks for posting your questions on the main forum.

    Gary's working to get you some answers, but can I ask for clarification on the question above: Do you really mean the focal plane -- the image sensor, or do you mean the nodal point? (See http://en.wikipedia.org/wiki/Cardinal_point_(optics)).

    That is, the point about which you need to rotate the camera and lens to avoid parallax?

    Thanks
    Andy.
     
  4. Gary Haynes

    Gary Haynes Administrator
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    Following up on Andy's question if it is the nodal point for parallax then you would need to add appropriate weight in the proper amounts to get the nodal center (vertical/horizontal/front to back) all aligned on the MōVI. While not impossible I don't think you would find it a all easy to do.

    Perhaps you can give some more information on how you want to use it, what you use today to achieve it?
     
  5. Fulvio Tonon

    Fulvio Tonon New Member

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    Hi Gary and Andy,

    Thanks a lot for your replies!

    I actually mean the nodal point because my application would be (outdoor) photogrammetry from a UAV, and I want the nodal/focal point of the camera to remain stationary with respect to the craft as the gimbal moves. I plan to either take photos when the craft is flying (e.g., 3-5 m/s) or stop and take photos at pre-defined waypoints; this depends on the specific application and morphology of the area.
    I currently do not have a UAV, and I am about to get one.

    Also: any word of wisdom as for MOVI5 vs. 2-way gimbal + radian for these applications?

    Thanks again!
    Fulvio
     
  6. Gary Haynes

    Gary Haynes Administrator
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    Fulvio I don't think that you will get the accuracy of flight that you are attempting in a consumer grade flight control system. Do you know of any commercial equipment that is doing something similar?
     
  7. Fulvio Tonon

    Fulvio Tonon New Member

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    Gary, When I shoot, I need to be 1-3 m from the intended waypoint, so the currently available flight control systems are fine. I will eventually get a Synapse + related distribution system and motors. Is there any release date for them?
    Cheers!
    Fulvio
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Fulvio: The problem, as you doubtless infer, is that the nodal point is not likely to be co-located with the center of gravity (CoG). To have the camera balanced, the CoG must lie on the tilt, roll, and pan axes for the gimbal to work correctly. This is particularly necessary for brushless gimbals where the brushless motors drive the axes directly. Somewhat less so with Radian/servo gimbals because they are belt driven and generate higher torque.

    As your application is photogrammetric, and I infer you are shooting still images, you could therefore use the Radian/servo gimbal to good effect and it would be more tolerant of any out-of-balance situation.

    Gary is correct though, you'd be better off to place the camera on the gimbal, determine the nodal point (by the usual means of swinging the camera and observing a near and far object), then contriving for the camera to be balanced at the same position by adding ballast to the camera.

    Does this help answer your questions, at least regarding the nodal point?

    Andy
     
  9. Fulvio Tonon

    Fulvio Tonon New Member

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    Excellent! Thanks so much, Gary and Andy!

    Best regards,
    Fulvio
     
  10. Chris Fox

    Chris Fox Active Member

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    Fulvio,

    I have been doing some photogrammetry work, and have been getting some pretty good result simply using the 2axis gimbal running from the MK flight controller.

    The MōVI is great for video, but for the photogrammetry work, I would consider saving some money and running a simple light weight 2axis gimbal.

    I have one CS8 set up like this which achieves some good flight times, and am in the process of building another to carry the MōVI, which will have shorter flight times due to the greater weight.

    Cheers
     
  11. Fulvio Tonon

    Fulvio Tonon New Member

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    Hi Chris,

    Thanks so much! BTW: one current limitation of taking photos manually from a regular helicopter (handheld camera) is that below shutter speed 1/250 images start getting blurred. Were you able to take stills at lower shutter speeds with your set up? Do you have a 2-axis Radian?
    Cheers!
    Fulvio
     
  12. Chris Fox

    Chris Fox Active Member

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    Fulvio,

    For photogrametric work, I set the camera to have a higher shutter speed, somewhere between 1/500 to 1/1000 that way any vibration or movement is not an issue, and I get sharp images.

    I don't have any radians, for this type of work I don't think you need them.
     

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