Solving steady state Kalman riccati equation

In the equation, AP + PA' + Q - PC'*inv®*CP = 0, I know C=1,Q,R are constant 2x2 matrices and A = [0 -q(k);q(k) 0], how do I solve for P in terms of the other variables?

Answer 1

[John Petersen]

Just write out the equations. If it's 2x2 it shouldn't be too hard. Q and R are almost always diagonal. P is symmetric, so these simplify things quite a bit. Since C is 1, that disappears too.