火星车绝对定位方法选择

针对火星巡视探测任务,提出3种火星车绝对定位方法:无线电测控定位、图像匹配定位、位置圆定位。无线电测控方法首先确定环绕器的轨道,然后利用环绕器和火星车的器间通信定位确定火星车的绝对位置;图像匹配方法利用着陆过程中的降落图像与带地理信息的着陆区地形图进行匹配,实现火星车的位置确定;位置圆方法通过敏感器在多个时刻测量阳光矢量方向和重力矢量方向,结合星历信息求解火星车的位置。对3种方法进行分析比较,根据定位精度、使用约束等因素,给出在轨使用建议:位置圆定位为基本方法,无线电测控定位作为校验手段,图像匹配定位作为修正手段,以满足火星车快速、高精度的定位需求。

Selection of Absolute Positioning Methods for Mars Rover

According to Mars moving detection mission, three absolute positioning methods for Mars rover are proposed:wireless TT&C, image matching, position circling. For the wireless TT&C positioning, the orbit determination is first done, then the rover position relative to the orbit is determined by wireless communicating between two detectors, at last the absolute position of the rover is calculated. For the image matching positioning, the absolute position of the rover is calculated by matching the images during the landing process to the map of the landing zone with geographic information. For the position circling, the orientation of the sun and Mars gravity is measured by sensors at discrete moments, then with these measured results and ephemeris the absolute position of the rover is calculated. The three methods are analyzed and compared, and using advice is given according to factors such as precision, constraints, etc. To get the rover absolute position rapidly and accurately, position circling acts as the primary method to get the position, wireless TT&C method verifies the position, and image matching method revises the position.