Dynamic analysis of DATE5 based on the physically realistic environmental disturbances

The observation bands of the 5 meter Dome A Terahertz Explorer (DATE5) are primarily over the wavelength of 350 and 200 μm. However, the pointing performance of DATE5 is affected by the unsteady wind, which either acts directly on the telescope structure or transmits through the ice and foundation. According to the above performance requirements of DATE5, the pointing error caused by the wind disturbance must be less than 2 arcsec. The main influence of the disturbances acting on the telescope is forces and torques due to wind gusts. Alternating forces and torques cause displacements of the telescope as well as structural oscillations. Both effects lead to pointing errors and therefore have to be compensated as much as possible by the main axes servo controllers. Wind acting on the telescope can be treated as random event, whose expected values depend on the specific site. The wind velocity throughout a given time interval can be described as a randomly varying velocity superimposed upon a constant average or mean velocity. For the dynamic analysis, the two components are separated and only the fluctuating component is used. In this paper, the dynamic analysis (mode analysis and spectrum analysis) of DATE5 is carried out based on the physically realistic environmental disturbances of dome A.