Hello. You do not need a Kalman filter to estimate a parameter. You should use a parameter estimation technique like recursive least squares or one of its variants. If the parameter is in fact part of a dynamic state space, so there are other variables you need to estimate at the same time, you can use a Kalman filter. In any case, the state equation for a parameter just says that the value does not change with time, i.e. x(k+1)=x(k) and you will typically have very little process noise on such states in the KF.
it depends on the system you are working on to estimate its parameters, where Kalman filter can be very efficient for time varying parameters. have a look to this paper .
Thank you Youssef Harkouss. Eduardo Freire Nakamura. Pavel Osinenko. Mohamed Ahmeid. Mudambi Ananthasayanam.
Thank you Graham W Pulford. I understand I do not need Kalman filter for parameter estimation. I just wanted to know if at all I uses it how will it work? Problem is solved.