[Dprglist] Compass heading using gyroscopes?

[Murray Altheim]

Hi Doug,

That's a good point. I frankly can't imagine why I'd need degree-perfect
accuracy on a moving robot, where the heading is changing quite a lot,
all the time. Now I suppose if one was using the heading reading to
*maintain* heading an accuracy of a few degrees would be valuable. So
there's two purposes: 1) basic directional navigation (e.g., pointing
the robot roughly north); and 2) heading with accuracy for holding a
bearing.

For directional navigation increasing resolution allows me to go from an
8-wind compass rose (an accuracy of 45° allows a determination of which
of the 8 directions we're aiming); 16-wind compass rose (22.5° accuracy);
32-wind compass rose (11.25°). So basically anything better than 11.25°
gives me a 32-wind compass rose for directional navigation. I think that's
easily doable.

For holding a bearing the more accuracy the better, though I doubt degree
accuracy is all that important in a small robot (a container ship, yes).
Since the robot is going to be reading the IMU and correcting its heading
continually a few degrees inaccuracy might be somewhat "self-correcting",
dunno. 2-3-5 degrees would probably be fine, but I won't know until I
try it out. The overall behaviour of the robot will be altered by that
difference but in either case I don't think it would be "wrong"; slow-
motion film of bumble bees shows they're hardly accurate navigators and
they seem to get along just fine.

Cheers,

Murray

On 15/05/20 6:26 pm, Doug Paradis wrote:
> Murray,
>     I think it also depends on the degree of accuracy you want. If you want your compass to tell you N,NE,E,SE,S,SW,W,NW 'ish, you calibration doesn't need to be as complete as if you want +/- 0.1 degree.
> 
> Regards,
> Doug P>
...........................................................................
Murray Altheim <murray18 at altheim dot com>                       = =  ===
http://www.altheim.com/murray/                                     ===  ===
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     In the evening
     The rice leaves in the garden
     Rustle in the autumn wind
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            -- Minamoto no Tsunenobu