On the choice of the aperture diameter of the probe laser in ground-based adaptive optoelectronic systems in the formation of a sodium reference star

• Main Authors: Victor V. Kleymionov, Elena V. Novikova, Maxim I. Oleynikov
• Format: Article
• Language: English
• Published: Saint Petersburg National Research University of Information Technologies, Mechanics and Optics (ITMO University) 2021-02-01
• Series: Naučno-tehničeskij Vestnik Informacionnyh Tehnologij, Mehaniki i Optiki
• Subjects: adaptive optical system; laser reference star; optical transfer function; atmospheric coherence radius; turbulent atmosphere; angular divergence of a laser beam
• Online Access: https://ntv.ifmo.ru/file/article/20181.pdf
• ISSN: 2226-1494; 2500-0373

Subject of study. The authors propose an integrated approach to the problem of determining the aperture diameter of a probe laser that forms a laser reference star used in ground-based adaptive optoelectronic systems. The relevance of this study is due to the fact that modern large-aperture optical systems for tracking natural stars and artificial objects (spacecraft or fragments of space debris) widely implement the technology of forming laser stars and use them as reference sources for correcting phase distortions of a turbulent atmosphere. The choice of the energy and spatiotemporal characteristics of laser guide stars is related both to the parameters of the probe laser (radiation power and aperture diameter), which forms the guide star, and to the spatiotemporal characteristics of the atmosphere. Method. The diameter of the probe laser aperture (for the near and far radiation zones) is estimated taking into account the spatial coherence radius of the atmosphere r0, the radiation intensity and angular divergence of the laser beam, its random root-mean-square angular deviation (jitter) with respect to the calculated direction to the space objects. Main results. The estimation of the angular divergence of a laser beam is based on a comparative analysis and generalization of theoretical results obtained by calculating the optical resolution in systems for acquiring images of natural space objects. It is shown, in particular, that when determining the size of the aperture along with the value of the angular divergence of the probe beam, it is necessary to take into consideration the decrease in its radiation intensity with an increase in the diameter with respect to the radius of atmosphere coherence. The practical significance. The results are essential, firstly, for the development of ground-based adaptive optoelectronic systems for tracking artificial space objects, and secondly, for determining the geographic locations of the optoelectronic systems taking into account the astronomical climate.