A multi-synchronous architecture to control an array of networked siderostats or telescopes at the Navy Precision Optical Interferometer

摘要

We present a multi-synchronous architecture for controlling multiple telescope or sidcrostat stations simultaneously from a central computer. This computer synchronously processes and distributes commands to six networked stations. The stations, comprised of a telescope or sidcrostat, a narrow angle tracker and a star-acquisition camera, are useful in the optical and infrared wavelengths. The central computer sends signed packets that include instructions for a particular station through the network at a rate of 600 Hz. A microcomputer at each station accepts its appropriate packets and parses the embedded data into control signals. These signals are then converted into appropriate outputs for motor controllers and piezoelectric actuators. The motors steer the siderostats while the piezoelectric actuators finely point the narrow angle tracker. A closed feedback loop couples the sidcrostat pointing with the narrow angle tracker to dynamically steer and maintain stable image positions of a stellar object. Two major components comprise this feedback loop: a wide-angle star acquisition camera inserted between a narrow angle tracker and sidcrostat, and a photon counter located near the end of the light path. The central computer utilizes positional error data from the camera to intricately align a sidcrostat. Simultaneously the computer processes pointing error derived from photon counts to finely correct a narrow angle tracker. This synchronized feedback and control system allows for precise, concurrent tracking over a wide range of stellar objects of interest. In this paper, we describe the parallelized software architecture, control hardware, experimental results, conclusions and recommendations.