Kablukova E.G. (Institute of Computational Mathematics and Mathematical Geophysics SB RAS, Novosibirsk, Russia), Prigarin S.M. (Institute of Computational Mathematics and Mathematical Geophysics SB RAS, Novosibirsk, Russia; Novosibirsk State University, Novosibirsk, Russia), Oshlakov V.G. (V.E. Zuev Institute of Atmospheric Optics SB RAS, Tomsk, Russia) MONTE CARLO SIMULATION OF A LASER BEAM IMAGE IN THE INSTRUMENTAL NAVIGATION SYSTEM