unobs

Arguments

A, C

real matrices

tol

tolerance used when evaluating ranks (QR factorizations).

n

dimension of unobservable subspace.

U

orthogonal change of basis which puts (A,B) in canonical form.

Description

[n,[U]]=unobs(A,C,[tol]) gives the unobservable form of an (A,C) pair. The n first columns of U make a basis for the unobservable subspace.

The (2,1) block (made of last nx-n rows and n first columns) of U'*A*U is zero and the n first columns of C*U are zero.

Examples

A=diag([1,2,3]);C=[1,0,0];
unobs(A,C)

See also

• contr — controllability, controllable subspace, staircase
• contrss — controllable part
• canon — canonical controllable form
• cont_mat — controllability matrix
• spantwo — sum and intersection of subspaces
• dt_ility — detectability test