Observation equations for baseline DSGE

Dear Prof. Pfeifer,

This is with regard to writing an observation equation to NH_baseline.mod My observable variable is the seasonally adjusted real GDP filtered using one-sided HP filter. Since mu_z and mu_A in the code capture growth trends in the data, in this case should the observation equation be?

y_obs = yd

Response in this matter is highly appreciated. Thanks in advance.

No, that is a problem. mu_z and mu_A contain frequency components that will not be fully removed by the one-sided HP-filter. As such, you cannot simply map to y_d. Your best hope may be something along the lines of