Processing angular rate and acceleration measurements obtained onboard the spacecraft Foton-12

This preprint presents the results of reconstruction of the uncontrolled attitude motion of the spacecraft Foton-12 by measurements of their onboard sensors. This problem was already solved successfully a few years ago. The motions of the spacecraft were reconstructed by measurements of the Earth magnetic field. But a lot of valuable measurement data, that were obtained on the spacecraft, have not been used essentially for this purpose. These data are angular rate and acceleration measurements carried out by the system QSAM. These data contain secondary clear-cut components of unknown origin and their presence made impossible an application of the data for reconstructing the spacecraft attitude motion. It was realized lately that those secondary components proved to be induced by the Earth magnetic field. Revealing this fact allowed to make a proper correction of the data and to use them for the reconstruction. The preprint contains descriptions of the correction procedures and results of their applying. The main results consist in the direct comparison of the motion reconstructed by angular rate or acceleration measurements with the motion reconstructed by measurements of the Earth magnetic field. The use of the corrected data proved to be successful.