Architecture of the metrology for the SRT

摘要

The Sardinia Radio Telescope (SRT) Metrology team is planning to install an initial group of devices on the new 64meters radio-telescope. These devices will be devoted for the realization of the antenna deformation control system: anelectronic inclinometer able to monitor the alidade deformations and a Position Sensing Device (PSD) able to map theantenna secondary mirror (M2) displacements and tilts. The inclinometer will be used to map the rail conditions, theazimuthal axis inclination and the thermal effects on the alidade structure. The PSD will be used to measure thesecondary mirror displacements induced by the gravity and by the thermal deformations that produce shifts and tilts withrespect to its ideal optical alignment. The PSD will be traced by diode laser installed on a mechanically stable positioninside the elevation equipment room. The inclinometer has been tested in laboratory with the aim to compare itsperformances with a reference measurement system. The PSD and the laser have been characterized by a long-term teststo assess their stability and accuracy, thus simulating the open air conditions that will be experienced by the deviceduring its operative life. M2 may move freely in space thanks to a six axis actuator system (hexapod). The PSDmeasurements are processed by a hexapod kinematic model (HKM) to evaluate the correct actuator elongations, thusclosing the control loop. The sensors will be acquired and recorded by a dedicated PC installed in the Alidade equipmentroom and connected to the sensors via the Ethernet network.© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.