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Sep 15, 2007, 03:45 PM
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Moving forward with the Kalman


Decided 2 move forward with the Kalman. It solved our biggest problem with algebraic navigation: loss of control when facing South. Flight tests with Kalman orientation hold + no GPS checked out perfectly. The 200Mhz Gumstix can only do 100 analog readouts/sec if the Kalman filter is doing 30Hz.

Position hold was a different story. GPS seems to feed up through the filter and cause it to lose orientation. However, the velocity curves making those lousy orientation results are the smoothest we've gotten.

Conclusion: need separate Kalman filters for orientation and position. 2 bad the money for a faster Gumstix was already spent on the EB-85 fiasco + monster rent inflation. The algebraic solution for orientation would need a fix for the South facing bug.

Hand tweeking the accelerometer center values got better velocity results. The accelerometer center point may indeed depend on the tilt that provides 0 acceleration reading as 0 deg tilt.

With 2 independant Kalman filters for position & orientation, the 200Mhz Gumstix only does 50Hz analog readings. Further tweeking with the conversion from world to copter frame got the first results that actually looked like what was really happening.
Last edited by Jack Crossfire; Sep 15, 2007 at 08:49 PM.
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