A Precise Attitude Determination and Control Strategy for Small Astrometry Satellite “Nano-JASMINE”

Intelligent Space Systems Laboratory (ISSL) Universityof Tokyo has developed a 35 kgastrometry satellite,“Nano-JASMINE”(Nano JAPAN Astrometry Satellite Mission for INfraredExploration)in cooperation with National Astronomical Observatoryof Japan (NAOJ). In the Nano-JASMINE mission, the satellite attitude spin rate should be controlled to an accuracy of 4 × 10−7 rad/s duringthe observation. To accomplish such severe attitude stabilization, we have developed two novelmethods. The first method is amagnetic disturbance estimation and compensation method. In conventional large satellites, a Magnetic torqueisnot the dominant attitude disturbance. However, in small satellites, the magnetic torqueis the dominant attitude disturbance.This is becausethe moments of inertia of small satellites are muchsmaller than those of the large satellites.Therefore, it is necessaryto developanovel magnetic disturbance estimation and compensation method. The second method is ahigh-accuracy spinrate estimation method. In small satellites, high-accuracyrate sensors which are widely used in large satellites are not available,since the power consumptions andthe sizes of thesesensors are too large for small satellites. Thus, we develop a new spinrate estimation method for Nano-JASMINE. This paper proposesthese two methods, the magnetic compensation and estimation method and the high-accuracyspinrate estimation method for the precise attitude estimationand controlin the Nano-JAMINE mission.The verificationresults with the simulations and the experiment show the effectiveness of these methods. The methods enable future small satellites to control its attitude more accurately