The paper presents feasibility and effectiveness of an innovative algorithm for spacecraft attitude determination, based on the real time fusion of raw data measurements provided by APS cameras, less limited by metrological constraints than traditional cameras used for star detection, and MEMS gyros, characterized by low-mass, low-power and low recurrent costs. The basic concept and the followed S&T methodological approach is described, which includes the use of cameras and gyros, even if the above basic concept states that gyros measurement data are neither strictly necessary, nor are increasing the attitude measurement accuracy in steady state conditions. Indeed, the availability of the gyro measurement data significantly contributes to the robustness of the spacecraft attitude measurement system particularly in “lost in space” and in “occulted camera” conditions. High quality gyros are not required. Angular rate measurements are fused with camera star measurements at raw data level. By the data processing the gyro attitude with respect to the “master camera” - denoted as “gyro on board attitude” - is estimated. The main novelty content and expected advantages with respect to the state-of-art are illustrated in detail, involving the following four main aspects: 1. fusion at the raw data level of all the gyro and camera measurements, what increases the spacecraft attitude measurement robustness and accuracy 2. Camera model self calibration. 3. Camera and gyro on board attitude estimation. 4. System scalability.
