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  • Dave Whittington March 26, 2010 at 3:55pm
    bGatti,
    I'm sure you are correct that it would behoove this approach to have quite a stable choice of aircraft - but perhaps an EasyStar is close enough for an eval. They have a real notion of pseudo-attitude drift compensation and it would simply be interesting to try it - if it worked well enough in certain situations (light winds,etc), just an ArduPilot board (no shields/thermopiles/IMUs, etc) with a GPS chip might be enough - seems hard to believe but why not try it!
  • Dave Whittington March 25, 2010 at 12:12pm
    I agree that there must be some real limitations, but wouldn't it be great to try it out if we could get their code(or at least a full set of their equations) - not for auto takeoff and landing but just for our normal autopilot fly-to-waypoints type mission. I would expect a lot of differences/problems but what is truly great about our Arduino ArduPilot environment is that "it's just code". We would make a test flight on a slightly windy day with our standard Ardupilot 2.5xx code and then their approach would be downloaded which would ignore our attitude sensors and just see what happens (BE READY TO GO TO MANUAL MODE!). Maybe we could approach them and see if they would be interested? Maybe we would learn something pretty cool that could integrate into our thinking - who knows!
  • Tj Bordelon March 25, 2010 at 7:00am
    This approach has it's limits. As Michael points out, I would wager that it only works well on calm days.
  • john bero March 24, 2010 at 9:35pm
    Integrators are designed to eliminate the steady-state errors on the velocity and position tracking errors. The aircraft speed is maintained at around 26 m/s except for takeoff and landing. Flare control uses forward speed/pitch/altitude. (twenty six meters per sec. Is that right? 62mph? This thing is a rocket ship)
  • Michael Zaffuto March 24, 2010 at 9:28pm
    Their controller is based entirely on the constraint of coordinated turns to keep turn rate and roll angle correlated. I suspect a few gusts of wind or shear from the right direction and its over.

    Not to take away from the fine implemenation from S.Korea....but....

    Let us take a moment now to bow our heads and give credit where credit is due:

    Kornfeld, Hansman and Deyst, of MIT, invented GPS Velocity Vector Based Attitude Determination, Report No. ICAT-99-5. June 1999. Contains all the theory for Single antenna GPS based pseudo-attitude and psuedo-flight angle(pitch) determination.
  • Developer
    Mark Colwell March 24, 2010 at 8:15pm
    Based on good old American software technology,

    credits from article:
    Manufacturers

    The reference station and UAV on-board receiver were both the 3151R from Novatel, Inc., Calgary, Alberta, Canada. The software for both onboard and ground stations was developed using Visual C++ with MFC, which runs on the Windows 2000/XP Professional operating system from Microsoft Inc., Redmond, Washington, USA. The data was plotted by using MATLAB from Mathworks, Inc., Natick, Massachusetts, USA.
    Copyright © 2010 Gibbons Media & Research LLC, all rights reserved.
  • Jack Crossfire March 24, 2010 at 8:05pm
    GPS derived attitude on anything small enough for our apartment would be incredibly noisy. You need a big airframe or RTK. The space shuttle may have used it & it was called 3 string GPS. NASA never published specifically whether 3 string GPS was used for attitude or just redundancy.

    Yes. Since every part is made in China, every UAV is a Chinese UAV whether it's team is in Korea, Australia, Japan, Europe, or that U country.
  • Developer
    Doug Weibel March 24, 2010 at 5:41pm
    Aside from the embarrassing post, the underlying article is pretty interesting. These guys are running a Kalman/DCM solution apparently with no gyro or accelerometer inputs, just mathematical/aerodynamic models and gps. Pretty cool IMO.
  • Simon Wood March 24, 2010 at 5:36pm
    Appologies - offense was not meant - despite my unwise choice of title.

    It's very interesting article.
    Simon.
    title.it
    description
  • automatik March 24, 2010 at 4:38pm
    Interesting....
    however post title says "Watch out, the Chinese are catching 'us' up... ;-)"
    and the article mentions that people involved in the project are from Seoul National University
    so it would be South Korean not Chinese catching up...:)
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