How to estimate state space model and designate matrix C=1 or [1, 0]?

I want to use some data to estimate a state space model of a dynamical system. I know I can use ssest command. Yet when I am using it, it returns model with very extrange C matrix very far from 1 or [1 0] (like C=15.6438 or C=[18.72 7.32], etc.). Yet I know from its characteristic that the dynamical system I want to identify has a trivial C matrix C=1 or C=[1 0]. Is there a way to designate the C matrix to be 1 or [1 0] when using ssest command to estimate the dynamical system? Or are there methods other than ssest to estimate the state space model of a dynamical system?

Answer 1

[Clayton Gotberg]

You are able to tell ssest which canonical form you expect the output to be in using the 'Form' option.

Ex:

ssest(data,order,'Form','companion') % sets to companion canonical form

You can also convert the system later using the canon function.

The documentation for canon explains what waht each canonical form is called in MATLAB.

[Jianning Cui]

It works! Thank you very much!