惯性信息辅助的星像点质心提取方法

针对振动环境中星敏感器曝光得到的模糊星像点质心提取精度低的问题,提出了惯性信息辅助的星像点质心提取模型并建立了相应的算法。算法以星像点区域的加权中心为曝光初始时刻的星像点质心,根据与星敏感器捷联的惯性设备测得的振动信息计算质心在曝光过程中的轨迹并利用星像点能量分布模型估计恒星的成像区域和加权中心,采用迭代的方法使得两加权中心重合,从而得到曝光结束时刻星像点质心的精确值。仿真分析了算法的质心提取精度及相关因素对提取精度的影响,结果表明算法在振动环境下仍可准确提取出星像点的质心,精度在百分之一像素左右,而且算法具有较好的适用性。

Star spot centroiding method with inertial measurement information

As for the low centroid precision of blurry star spots acquired by the star sensor in vibration environment, the star spot centroiding model aided by inertial measurement information is proposed here and the centroiding algorithm is formed. The weighted center of the star spot is regarded as the centroid at the initial time of the exposure course by the algorithm, then the centroid track can be computed with the vibration information by the strap-down inertial sensor, and the star imaging area and its weighted center can be estimated with the star spot power distribution model, finally the exact centroid at the finish time can be got by using iterative operation to make the two weighted centers coincide with each other. The centroiding precision of the algorithm and the effect of relevant factors on it are analyzed using simulation data, and the numerical results indicate that the method can reach about 0.01-pixel centroid precision even at the vibration environment with a good applicability performance.