Control System Toolbox Function Reference

obsv

Form the observability matrix

Syntax

Ob = obsv(A,B)
Ob = obsv(sys)

Description

obsv computes the observability matrix for state-space systems. For an n-by-n matrix A and a p-by-n matrix C, obsv(A,C) returns the observability matrix

with n columns and np rows.

Ob = obsv(sys) calculates the observability matrix of the state-space model sys. This syntax is equivalent to executing

Ob = obsv(sys.A,sys.C)

The model is observable if Ob has full rank n.

Example

Determine if the pair

A =
     1     1
     4    -2

C =
     1     0
     0     1

is observable. Type

Ob = obsv(A,C);

% Number of unobservable states
unob = length(A)-rank(Ob)

MATLAB responds with

unob =
     0

See Also
obsvf       Compute the observability staircase form

nyquist

obsvf