How to solve the algebraic Riccati equation for Y infinit?

Hello everyone, I have the following code: g = 35200; A = [0 0 1 0; 0 0 0 1; 0 673.07 -35.1667 0; 0 -1023.07 35.1667 0]; B = [0; 0; 61.7325; -61.7325]'; B1 =[0 0 0 0]'; B2 = B; C1 = [1 1 0 0]'; C2 = [1 1 0 0]'; C = [C1, C2] m1 = size(C1,2) m2 = size(C2,2) R = [-g^2*eye(m1) zeros(m1,m2) ; zeros(m2,m1) eye(m2)] Y = care(A,C,B'*B,R) Implementing this code obtain the error of "Unable to solve the specified Riccati equation because the Hamiltonian spectrum istoo close to the imaginary axis".

Any one can solve it to get the Y matrix plz??

Thanks in advance ^_^

Esmail Ali