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dcm

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### Activity Feed

johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Bill
thanks very much .
I got it.

thanks"
May 1, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear Bill
"Magnetometer is used for yaw compensation."

Thanks"
Apr 25, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Very sorry to trouble you so many times. I have understood and let me answer some of the question myself.
>question 2: >we take the cross product Z row of estimated DCM with the gravity reference vector
>and if the result is not ZERO, you call it…"
Apr 22, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
regarding COG and roll-axis, we only need the Z component
while gravity and  Z row of DCM, we nee the whole cross product
may i know the reason"
Apr 22, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear I have new questions
regarding the RollPitchCorrection ,we use the accelerometer to obtain a gravity reference vector
question 1:
when we use it ,is there an assumption made that the plane keep going forward in a horizontal level?
question…"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear I have new questions regarding the RollPitchCorrection we use the accelerometer to obtain a reference vector ( the Z-axis in plane frame) and the assumption is made that the"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"new diagramIMG_20160422_125659.jpg"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"new draft"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear I reviewed the Eqn14~17 which someone feels confused maybe. would it be better if we add some tips or comments about this setction 1. the θ(x/y/z) in the matrix of Eqn 17 stands for the magnitude of the Vector : dt * W(x/y/z) X r(t) not the…"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear
I can understand it now.

Thanks"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"sorry for the stupid question .
I have known it .
the sign is negative if exchange the cross product of them"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
for example. the x-axis has the whole Centrigual acceleration(Vector C). the Gravity works in z-axis (Vector G)
under this condition. the Accelerometer will output the result  Vetor  A = C + G
so if we want to get the G, we need A-C,but…"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear
Regarding the Eqn 26 in the paper(DcmDraft2)
I think
the acceleromter is aligned with the plane(body).so its output is the combination result of gravity and centrigual acceleration.
and we only need the gravity acceleration as our reference…"
Apr 21, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear  Bill
quote:
the bottom row of the direction cosine matrix should be aligned with the vector produced by the accelerometers

May I know the reason why these two vectors should be aligned ?under what condition?
because,from the earth frame. the…"
Apr 20, 2016
johnson replied to William Premerlani's discussion robust estimator of the direction cosine matrix
"Dear Bill