基于分段常值的全电推进GEO卫星制导策略

Guidance Strategy for All-Electric Propulsion GEO Satellite Based on Piecewise Constant Thrust

电推进技术因其比冲高的技术特点在GEO轨道转移中应用可大大减少燃料质量,提高有效载荷质量比,延长任务寿命等。针对全电推进GEO卫星入轨的轨迹优化和制导问题,首先利用间接法获得小推力燃料最优GEO轨道转移的数值解,提出一种多项式曲线拟合最优轨迹的方法,多项式曲线形式简单,可作为参考轨道在星上存储和使用。在多项式参考轨道的基础上,建立了一种分段常值推力跟踪参考轨道的闭环制导策略,在常值推力条件下,轨道要素控制量与控制力有解析关系,简化了制导律设计;将多圈轨道转移问题分解为多个单圈轨道优化问题。结果显示,提出的分段常值跟踪制导策略跟踪精度高,和最优轨道相比多消耗7%的燃料。本制导策略控制结构简单,易于工程实施。

Due to the high specific impulse,the application of electric propulsion technology in GEO orbit transfer can greatly reduce the fuel mass,improve payload mass ratio and prolong mission life.In order to solve the trajectory optimization and guidance problem of all-electric propulsion GEO satellite,the indirect method is used to obtain the numerical solution of fuel-optimal GEO orbit transfer with low thrust,and a polynomial curve fitting method is proposed to fit the optimal trajectory.The polynomial curve is simple in form and can be stored and used onboard the satellite as a reference orbit.On the basis of polynomial reference orbit,a closed-loop guidance strategy using piecewise constant thrust by tracking the reference orbit is established.Under the condition of constant thrust,there is an analytic relationship between the control structure and the change of the orbit elements,which simplifies the design of guidance law.The multiple-revolutions transfer problem is decomposed into multiple single orbit optimization problems.The results show that the proposed guidance strategy has high tracking accuracy and consumes 7%more fuel than the optimal trajectory.The control structure of the guidance strategy is simple and easy to implement.