Flight results of precise autonomous orbit keeping experiment on PRISMA mission

The autonomous orbit keeping experiment on the PRISMA mission was executed successfully from 18 July to 16 August 2011 and has demonstrated the capability of autonomous precise absolute orbit control. Using GPS-based absolute navigation data, the onboard controller commanded thruster activations in the orbital frame to autonomously control the satellite’s longitude of the ascending node within a predefined window. The main performance requirement of the experiment was a control accuracy of 10 m (1σ) with a maneuver velocity increment and decrement available budget of 0.5 m/s. After a four day commissioning phase, the reference orbit was acquired. A 3.5 day controller tuning was then followed by the fine orbit control phase, which commenced on 30 July 2011 and continued until the end of the experiment. The control accuracy requirement was fulfilled. The mean value of the longitude of the ascending node’s deviation was −3.6 m with a standard deviation of 9.5 m during the fine control phase. The total Δv spent during the entire experiment was 0.1347 m/s, corresponding to 27% of the maneuvers budget allocated