火星车定向天线自主对地指向规划方法

Autonomous Earth Pointing for Mars Rover High-gain Antenna

针对火星车的2自由度定向天线,结合在轨约束条件和对地数传需求,提出一种基于解析星历的器上自主对地指向规划算法。首先给出火星和地球的相对方位、信号传输时延和空间交会的解析计算公式,摆脱了复杂的星历表模型,使得器上计算机运行更加高效;在此基础上根据火星车位置和姿态、定向天线安装矩阵,计算定向天线的转角,并给出天线转轴运动控制策略,使其实时自主跟踪地球,建立稳定运行的通信链路。通过仿真对解析星历计算结果进行检验,并在室内试验场对天线自主跟踪结果进行验证,仿真和试验结果表明该方法合理可行,指向精度满足使用要求。此方法解决了大时延下火星车定向天线对地球的指向和跟踪问题,将会应用至我国的首个火星车上。

For the two-dimension high-gain antenna of the mars rover, with consideration of the onboard restrictions and demands of transmission to the earth, an autonomous earth pointing algorithm is proposed based on analytical ephemeris. In the algorithm analytical formulas of mars-earth relative azimuth, signal transmission delay, and space intersection are presented, which gets rid of the complicated ephemeris model and makes the onboard computer running more efficiently. On this basis, the antenna rotation angles are calculated according to the position and posture of the rover, installation matrix of the high-gain antenna. And control strategy of the antenna joints is given to make the antenna autonomously track the earth in real time, which would build stable communication link. The calculated results of analytical ephemeris are tested by simulation, and the autonomous tracking results of antenna are verified in laboratory. Simulation and test results prove that the method is reasonable and feasible, and pointing accuracy meets the requirements. This method solves the earth pointing and tracking problem of antenna in long delay condition, and will be used on the first mars rover of China.