Active reflective surface shape adjustment method based on axial gain measurement

Abstract

The invention discloses an active reflective surface shape adjustment method based on axial gain measurement. According to the method, a series of micro-disturbance is applied to a reflective surfaceshape through an actuator network in an active surface system, and the change in antenna axial gain is measured in the disturbing process; a group of orthogonal basis functions defined on an antenna port surface are used as disturbance modes to disturb the surface shape one by one, and under each disturbance mode, a curve of the change in the antenna axial gain along with the disturbance quantityis recorded, and the optimal adjustment quantity under each disturbance mode is fitted out of the corresponding curve; and through a series of disturbance, measurement and adjustment processes, finally the antenna gain can reach a maximal value, and the surface shape error can reach a minimal value. The method has a low requirement on a detector, and a single-pixel power detector can be used; in the running process of a telescope, a scientific receiver and an astronomical point source target can be directly utilized to carry out surface shape measurement and adjustment frequently, and therefore the observation efficiency of the telescope in the running process is maintained.

Description

technical field [0001] The invention relates to an active reflection surface shape adjustment method based on axial gain measurement, which is mainly applied to large radio telescopes. Background technique [0002] For radio telescopes in the form of reflector antennas, the surface shape accuracy of the reflector is an important performance index, which directly determines the highest frequency band that the telescope can work and the observation efficiency. The main reflector of modern large radio telescopes is usually spliced ​​by panels of smaller size. These panels are supported and actively adjusted by displacement actuators, and finally spliced ​​into the required large-aperture reflector. Such reflector forms are also called active reflectors or active surface systems. Although the active surface system reduces the difficulty and cost of reflector processing, it requires To adjust hundreds of meters-sized panels to their ideal positions, the maximum allowable deviati...

AI Technical Summary

Problems solved by technology

For example, radio holographic measurement requires a coherent signal source as a beacon, and the telescope is equipped with a dedicated holographic receiver and a reference antenna or horn that provides phase reference, so this method is mainly used in the antenna assembly stage, and cannot be used in the telescope operation Surface shape measurement directly using scientific receivers during the process

In addition, factors such as reference phase drift and reference antenna phase pattern measurement errors will introduce system measurement deviations and affect the final surface shape adjustment accuracy

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