px4-firmware/matlab/scripts/Inertial Nav EKF/Quat2Tbn.m

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468 B
Matlab

function Tbn = Quat2Tbn(quat)
% Convert from quaternions defining the flight vehicles rotation to
% the direction cosine matrix defining the rotation from body to navigation
% coordinates
q0 = quat(1);
q1 = quat(2);
q2 = quat(3);
q3 = quat(4);
Tbn = [q0^2 + q1^2 - q2^2 - q3^2, 2*(q1*q2 - q0*q3), 2*(q1*q3 + q0*q2); ...
2*(q1*q2 + q0*q3), q0^2 - q1^2 + q2^2 - q3^2, 2*(q2*q3 - q0*q1); ...
2*(q1*q3-q0*q2), 2*(q2*q3 + q0*q1), q0^2 - q1^2 - q2^2 + q3^2];