Reflector surface alignment based on antenna gain measurements under perturbations

Abstract. We describe a method for the measurement and alignment of reflector surfaces of radio telescopes with high precision. The scheme is based on antenna gain measurements under a series of active surface perturbations in terms of a set of orthogonal basis functions. Both local and global basis functions can be employed, resulting in different spatial resolution and different requirements on signal-to-noise ratio. Both theoretical studies and numerical simulations are presented, and demonstration experiments on a 1.2-m submillimeter antenna are reported. Practical considerations, including the effects of antenna mispointing and near field operation, are also discussed.

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