Observability: PBH test

• The matrix has full column rank for all *l* in **C.
**

•** **Let *l* and *y* be any
eigenvalue and any corresponding

right eigenvector of *A*, i.e., *Ay= **l**y*, then** ***Cy**¹** 0.
*

• *(C, A)* is
observable if and only if (*A*****,C**) is controllable.