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54 lines
1.2 KiB
Matlab
54 lines
1.2 KiB
Matlab
function q = AttiudeFromVectors(mag,north,accel)
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% q = AttiudeFromVectors(mag,north,accel)
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ge = [0 0 -9.81]';
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ge = ge / sqrt(ge' * ge);
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mag = mag / sqrt(mag' * mag);
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north = north / sqrt(north' * north);
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accel = accel / sqrt(accel' * accel);
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Rib(1,:) = mag;
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Rib(2,:) = cross(mag,accel);
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Rib(3,:) = cross(Rib(1,:),Rib(2,:));
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Rie(1,:) = north;
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Rie(2,:) = cross(north,ge);
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Rie(3,:) = cross(Rie(1,:),Rie(2,:));
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R = (Rib' * Rie)';
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m = [1 + R(1,1) + R(2,2) + R(3,3); ...
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1 + R(1,1) - R(2,2) - R(3,3); ...
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1 - R(1,1) + R(2,2) - R(3,3); ...
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1 - R(1,1) - R(2,2) + R(3,3)];
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[mag,idx] = max(m);
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mag = 2 * sqrt(mag);
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if (idx == 1)
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q = [mag/4; ...
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(R(2,3)-R(3,2))/mag; ...
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(R(3,1)-R(1,3))/mag; ...
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(R(1,2)-R(2,1))/mag];
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elseif (idx == 2)
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q(2) = mag/4;
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q(1) = (R(2,3)-R(3,2))/mag;
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q(3) = (R(1,2)+R(2,1))/mag;
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q(4) = (R(1,3)+R(3,1))/mag;
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elseif (idx == 3)
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q(3) = mag/4;
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q(1) = (R(3,1)-R(1,3))/mag;
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q(2) = (R(1,2)+R(2,1))/mag;
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q(4) = (R(2,3)+R(3,2))/mag;
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else
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q(4) = mag/4;
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q(1) = (R(1,2)-R(2,1))/mag;
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q(2) = (R(1,3)+R(3,1))/mag;
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q(3) = (R(2,3)+R(3,2))/mag;
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end
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if (q(1) < 0)
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q = -q;
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end
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q = reshape(q,[],1); |