星图质心提取的实时性研究  

The Research of Fast Centroid Locating for Star Image

作　　者：樊晓宇[1] 江浩[1] 

机构地区：[1]第二炮兵工程学院,西安710025

出　　处：《航天控制》2011年第5期48-52,共5页Aerospace Control

摘　　要：数据更新率是衡量星敏感器性能的一个重要参数,高数据更新率对质心提取的实时性提出了更高的要求。FPGA(现场可编程门阵列)具有快速逻辑运算和并行处理结构的特点,针对这些特点对质心提取过程进行研究。使用FP-GA内部的高速存储器作为缓存,提高对数据的读取速度。将质心提取中的阈值分割、星点像素提取和质心计算3个过程进行并行处理,质心提取算法采用定位精度较高的高斯曲面拟合法,给出了各个过程的FPGA具体实现方法。使用计算机和硬件电路相结合的方式进行试验仿真,结果显示:当时钟频率提高到150MHz时,运算电路仍能正常工作,计算一幅512×512星图的时间小于4ms,在信噪比小于0.05的情况下,定位精度小于1/20像素,表明使用FPGA可以实现对星图目标质心的快速、精确提取。The update rate is a key characteristic for star sensor. The higher update rate responds from faster centroid locating. The process of centroid locating is investigated by the characteristics of high logical calculation speed and parallel process structure of field programmable gate arrays （FPGA）. In order to get higher data read speed, the on-chip-ram of FPGA which has high work speed is used as buffer. The algo- rithm for image threshold divided, star pixel recognition and Gauss curve fittting methods are implemented in parallel by FPGA. A simulation is built by combining the computer with the hardware circuit. The results show that the circuit is working in order when the clock frequency is up to 150MHz. It spends less than 6ms to process a 512 x 512 star image and the locating precision is less than 1/20 pixel when signal-to-ratio is less than O. 05. It indicates that centroid can be located accurately and fast by using FPGA.

关 键 词：星敏感器 质心提取 高斯拟合法 FPGA 并行处理 

分 类 号：V448.22[航空宇航科学与技术—飞行器设计]