一种地月转移轨道中途修正的制导算法

针对地月转移轨道中途修正问题，提出了一种求解修正速度增量的制导算法。该算法由初值设计和精确解求解两部分组成。首先，利用伪状态理论，通过简单迭代设计中途修正的初值，并通过Vinti预报方法修正了地球扁率的影响。然后，在求解精确解时，提出了一种基于伪状态理论的状态转移矩阵解析算法。该算法通过设计高精度的初值，降低了求解地月转移轨道中途修正问题的难度，而且避免了传统数值方法计算状态转移矩阵的复杂性。数值仿真结果表明，该算法可有效求解中途修正问题。

A guidance algorithm for mid correction of trans lunar trajectory

A new guidance algorithm for mid correction of trans lunar trajectory was presented. The algorithm was divided into two steps, i.e.,designing the initial solution and searching for the exact solution. First, the initial solution was generated using the pseudostate theory, and the Vinti prediction was adopted to improve the accuracy of the initial solution by eliminating the earth oblateness effect. Then, while searching for the exact solution, the state transition matrix was calculated by an analytical method based on the pseudostate theory. Because the initial solution with high accuracy is used, the difficulty of finding the solution for mid correction of trans lunar trajectory is greatly reduced. Moreover, the calculation of the state transition matrix by using traditional numerical methods is omitted. Numerical simulations indicate that the algorithm is of high efficiency.