The task of angular orientation and stabilization of a space structure during its
assembly in orbit is solved. The structure includes elastic elements that are installed during the
assembly process. The elastic elements of the structure have no sensors to obtain information
about their deformation parameters. Control algorithms are proposed to ensure the stability of
the angular motion of the structure. A nonlinear extended Kalman filter is used to obtain the
necessary information. A joint estimation algorithm for the coordinates of the angular motion
of the considered mechanical system and the coordinates of the elastic vibration tones, as well
as an algorithm for the identification of their unobservable parameters are developed. The
results of mathematical modeling of a variant of the mechanical system of a space structure
are presented, which confirm the operability and efficiency of the developed algorithms for
estimating coordinates and parameters.