重力梯度力矩作用下近地卫星自旋运动规律分析

Analysis of the law of LEO satellite spin motion under the influence of gravity gradient torque

为研究近地卫星自旋运动规律,建立了近地卫星在受摄动影响的轨道上运行并受重力梯度力矩作用下的姿态运动模型,推导了自旋角速率满足一定条件下自旋运动的进动角、章动角、自旋角的解析解,对重力梯度作用下的自旋姿态运动规律进行了仿真分析,并用仿真计算结果验证了解析解的正确性。在轨道面缓慢进动情况下,当卫星绕最大主惯量轴自旋时,给出了自旋角速率取值范围表达式,在该取值范围内卫星自旋运动能够跟随轨道面一起进动,自旋轴以恒定的平均角速率进动,章动角在小范围内波动。建立的自旋姿态运动模型和分析结论可用于近地卫星姿态失控后的姿态确定和预测、在轨姿态设计及在轨备份等。

In order to study the law of LEO satellite spin motion,for the LEO satellite whose ascending node right ascension precesses slowly,its attitude motion model under the influence of gravity gradient torque was established.Besides,the analytical solutions of the precession angle,nutation angle and spin angle were derived when the spin angular rate met certain conditions.Also,the correctness of the analytical solutions was verified by simulation results.In the circumstance that the orbital plane precesses slowly,when the satellite spins around the maximum principal inertia axis,the value range of the spin angular rate was given,and within this range,the spin motion of the satellites can precess with the orbital plane simultaneously,the spin axis can precess at a constant average angular rate,and the nutation angle fluctuates on small scales.When the attitudes of the near-Earth satellites are out of control,the established model on the attitude motion of spinning as well as the analysis conclusions can be used to estimate and predict the attitude.They can also be used for the design of on-track attitudes as well as on-track backups.