A Study On Attitude Determination And Control Of Gravity-gradient Stabilized Satellite

Satellite miniaturization has become a trend in today’s satellite development. Inparticular, modern small satellites has great economic advantage and compelling effect,make the modern small satellites, micro-satellite go into the new world.This thesis is mainly to study the attitude determination、 precise orbitdetermination and active magnetic control of gravity-gradient stabilized satellite.First of all，the definition of the reference coordinate system and the conversionbetween coordinate systems are given.The ways of the described in satellite attitude isstudied, and, compare their advantages and disadvantages,the satellite attitude motionequations and attitude dynamics equations are established,analyzing the torque on thesatellite at different heights in space.The second，this thesis gives a brief discussion for the major satellite attitudemeasurement method and principle. Discussed on the mainstream attitude sensorsnow,designed two methods of attitude determination of attitude sensor combinations,and make a comparison of the simulation.Studied a method of gravity gradientstabilized satellite orbit determination:GPS Zero-Differential kinematic orbitdetermination,designed two kinds of orbit determination of solved and need solvingambiguity. Systematic analysis of the two programs orbit determination accuracy.The third，study the method of gravity gradient boom’s stretching program.Proposed two major research programs under the conditions of magnetic. One isdesigned fixed speed to stretch gravity gradient boom. The second is at the condition ofmagnetic moment and the star’s attitude angle and angular velocity to finish the thestretching of gravity gradient boom by logical attitude feedback loop. And demonstratedthe feasibility of the design by simulation.On the basis,discussed the selection principleof gravity gradient boom’s length.Finally，discussed magnetorquer working principle and mathematical model,designed a control rate during Velocity Damping of satellite after the satellite separatedfrom the rocket.Designed two strategies of gravity gradient boom’s stretch,and gettedcorresponding simulation.According to quaternion feedback magnetron law and Eulerangles feedback quaternion feedback,designed PD Active magnetic Algorithm.