A shielding apparatus for electromagnetic testing comprises a platform, a lid, a driving unit, a pulley system, and a counterbalance. A desired bias level is set based on a temperature-dependent reference signal. An identity of a second process that is a distinct instantiation of the first application is authenticated using a second digital certificate distinct from the first digital certificate. An azimuth data output section outputs the azimuth data based on substantially newest measurement data and the offset data.