Surface adjustment strategy for a large radio telescope with adjustable dual reflectors

Abstract

With the development of large-aperture and high-frequency radio telescopes, a surface adjustment procedure for the compensation of surface deformations has become of great importance. In this paper, an innovative surface adjustment strategy is proposed to achieve an automated adjustment for the large radio telescope with adjustable dual reflectors. In the proposed strategy, a high-precision and long-distance measurement instrument is adopted and installed on the back of the sub-reflector to measure the distances and elevation angles of the target points on the main reflector. Here, two surface adjustment purposes are discussed. The first purpose is to ensure that the main reflector and the sub-reflector are always positioned at their ideal locations during operation. The second purpose is to adjust the main reflector to the location of the best fitting reflector, and the sub-reflector to the focus of the best fitting reflector. Next, the calculation procedures for the adjustments of the main reflector and the sub-reflector are discussed in detail, and corresponding simulations are carried out to verify the proposed method. The results show that the proposed strategy is effective. This paper can provide helpful guidance for the design of automated surface adjustments for large telescopes.

Panel Adjustment and Error Analysis for a Large Active Main Reflector Antenna by Using the Panel Adjustment Matrix

“…Regardless of the actuators being shared at the adjacent corners of the adjacent panels, the calculation processes of the adjustment values are identical. The only difference is that the panel adjustment matrix is derived using (9) or (14) for the independent or shared actuators, respectively. In general, the difference between the deformations at the adjacent corners of the adjacent panels is small because the surface deformation is nearly continuous.…”

“…In general, the difference between the deformations at the adjacent corners of the adjacent panels is small because the surface deformation is nearly continuous. Thus, to calculate the adjustment value of the shared actuator at the adjacent corners of adjacent panels, in addition to the method using (14), another simple method is to adopt the average value of the adjustment values of the independent actuators at the adjacent corners as the approximation value of that of the shared actuator.…”

“…Two compensation methods are commonly applied. The first approach involves moving the subreflector for the nonactive main reflector antenna through one six bar mechanism, and the second approach is to adjust the panels for the active main reflector antenna through thousands of actuators [14]. Reference [15] presented a subreflector adjustment method to compensate for the main reflector deformation through the surface piecewise fitting of the deformed main reflector.…”

Dynamic Disturbance and Error Analysis of Flexible Support System for Large Optical Mirror Processing

“…With the information revolution, modern optical mirrors are being developed for large apertures and high precision [1][2][3]. These large apertures and precision requirements have increased the difficulty of processing, and the requirements for the processing equipment have also increased [4].…”

Multi-Objective Parameter Optimization of Flexible Support System of Optical Mirror

“…With the development of information technology, modern optical mirrors are being enhanced rapidly toward large apertures and high precision [1,2]. The increase in the requirements with regard to optical mirror aperture and precision has increased the difficulty of processing, as well as the requirements for processing equipment [3,4].…”