Aerospace Instrument-Making Annotation << Back A METHOD OF IN-FLIGHT CALIBRATION FOR SPACECRAFT REDUNDANT INERTIAL MEASUREMENT UNIT I.V. Solovyev, N.V. Ryabogin This paper presents a novel method of on-orbit calibration for spacecraft redundant inertial measurement unit (RIMU) with four sense axes. A calibration error model comprises 16 parameters: 4 gyro biases, 4 scale factor errors, and 8 misalignment angles of the sense axes with respect to their nominal directions. An algorithm based on the least squares method is developed for estimation of all 16 calibration parameters through measurements of both RIMU and star sensor processed on board and partially on the ground. The measurements are obtained during a calibration maneuver with duration of not less than 1.5 hours consisting of spacecraft consecutive rotations around RIMU coordinate system axes. It is shown that the proposed algorithm provides complete observability of all estimated calibration parameters. Simulation results demonstrate the efficiency of the present method. It can be directly used for in-flight RIMU calibration of the prospective spacecraft «Spectrum-RG» and, after straightforward generalization, for in-flight calibration of the other redundant angular rate measuring instruments with multiple sense axes. Key words: calibration, redundant inertial measurement unit, spacecraft. Contacts: E-mail: i.solovieff@yandex.ru, E-mail: ryabogin@mokb-mars.ru Pp. 11-21.