Before you can perform this task, you must have regularly-sampled, steady-state time-domain data imported into the System Identification app. See Import Time-Domain Data into the App). For transient data, see How to Detrend Data at the Command Line.
In the System Identification app, drag the data set you want to detrend to the Working Data rectangle.
Detrend the data.
To remove linear trends, select Preprocess > Remove trends.
To remove mean values from each input and output data signal, select Preprocess > Remove means.