MATLAB: A(I) = B error.

a(i) = ba(i)=barraykalman

This is what the error says "In an assignment A(I) = B, the number of elements in B and I must be the same.
Error in KF (line 6)
Xhat(i) =zeros(3,1);
How do I solve this.
A = [0.7474 0.453 0.0735; -0.441 -0.06106 0.01205; -0.0723 -0.5735 -0.1334]; 
B = [0.0421 0.0735 0.01205]'; 
C = [20 9 1]; 
U = 0; H = 1;
z = -0.37727 + 0.1*randn(50,1)
Xhat(i) =zeros(3,1);
P = eye(3,3);
Q = 0.00001
R = 0.01
for(i=2:50)
    X_(i) = A*Xhat(i-1) + B*U;
    P = A*P*A' + Q;
    K = P*H'*inv(H*P*H' + Q)
    Xhat(i) = X_(i) + K*(z(i)-H*X_(i));
    P = (eye(1,1)-K*H)*P;
end
figure
plot([1:50],z,'rs')
hold on
plot([1:50], -0.37727*ones(1,50),'k')
plot([1:50], Xhat,'g')

Best Answer

That’s actually fairly straightforward. You’re assigning a (3x1) vector vector of zeros to a scaler Xhat(i). That won’t work. Either:
Xhat(i) = 0;                % Scalar Assignment
or:
Xhat(i,:) = zeroes(3,1);    % Vector Assignment
You later refer to a subscripted ‘Xhat’. so the second version is likely what you want.
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