New to the forums.. questions about AQ6 GPS+INS fusion

Info and discussion about the original AQ v6 flight controller

Re: New to the forums.. questions about AQ6 GPS+INS fusion

Postby srinath » Thu Apr 24, 2014 5:39 am

An excellent introduction to Kalman Filters is the one by Welch Bishop (Google It)
Then i would suggest reading Van Der Merwe's thesis

At the end of the day, the KF, EKF, UKF etc are all stochastic observers that have the same structure as a Luenberger observer. In fact in the deterministic world the LQR control problem may be reformulated as a dual observer problem.
If the filter converges, the steady state Kalman gains will be as predicted by LQR theory

An aspect not covered usually is the closed loop behavior of KF + controller.
KF may have very low estimation error, but if it has poor frequency response there will be lag and possible instability in the closed loop.
An alternate approach is the Functional Observer architecture, which guarantees good robustness of the closed loop system, while maintaining the separation principle (Design of Observer and Controller should be separate).
My goal is to make a Functional UKF and develop methods to estimate the phase loss in the UKF

For INS-GPS integration i refer to "Strapdown Inertial Navigation" by "Titterton and Weston"
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Re: New to the forums.. questions about AQ6 GPS+INS fusion

Postby SiggiSig » Thu Aug 28, 2014 11:21 pm

Is this thread dead or what ?
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Re: New to the forums.. questions about AQ6 GPS+INS fusion

Postby zhlearnaq » Mon Mar 02, 2015 2:22 am

@aharmon, hello, can i ask you some question about GPS fusion? I have notice that there are three delays(GPS_LATENCY, UKF_POS_DELAY, UKF_VEL_DELAY) in the code, what dose them mean and how to choose the value?
To realize positioning, i put an eye on the GPS raw value, i got the distance value by lat and found the value jumped by 40cm at one time, is it normal or i have the wrong value?(my GPS model is Portable)
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Re: New to the forums.. questions about AQ6 GPS+INS fusion

Postby ilyaprok » Mon Aug 29, 2016 5:45 pm

HI. I'm a student. Recently I became interested in the subject of UKF. I am interested in how you were looking for factors of noise variances UKF_VEL_Q, UKF_VEL_ALT_Q ... UKF_VEL_DELAY. Also interested in what is needed SRCDKFMeasurementUpdate_t * map. I would be very grateful for answers! :)
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