Accuracy estimation of determining attitude of coordinate systems of BOKZ-M60 star sensor

We investigate the accuracy of measurement data that were obtained during testing BOKZ-M60 sensor in the special testbed in RSSI RAS. The testbed has a movable platform, where the sensor BOKZ-M60 scanning the sky is fixed. The platform has three degrees of freedom and moves according to PC program. But its motion is not known with a sufficient accuracy. Extraneous measurements of the platform motion are complicated and expensive. Therefore, first, we approximate the motion of the platform using the suitable mathematical model. The model represents the motion as a combination of two Euler rotations. The first rotation describes the rotation of the Earth; the second one is caused by periodic oscillations of the platform. The parameters of both rotations are determined by sensor measurements. Then we analyze the residues of the found approximation and estimate by them the sensor accuracy. The errors of sensor measurements depend on a type of platform motion and are in the range from 2 to 25 arc seconds.