提出一种基于改进空间频率域(UV)采样的阵列评价函数, 用于长基线天文光干涉望远镜阵列几何结构的优化。该评价函数将UV采样区域沿径向和角度方向分别进行划分, 统计划分所得区域中UV采样点数目并计算UV采样点密度, 以UV采样点密度偏离理想高斯分布的大小作为评价依据。在具体的优化技术上, 利用遗传算法的全局收敛特性, 降低了传统算法对初始结构的依赖, 采用该评价函数对6孔径望远镜阵列进行优化设计, 并与国际主流天文光干涉阵列CHARA进行了性能对比。分析结果表明: 优化所得Array-6阵列UV采样点密度分布具有径向连续覆盖和低频强调的特点, 有利于对轮廓信息的恢复; 双星模拟成像实验中Array-6阵列重构图像相对于原始图像的误差为21.34, 相比CHARA阵列降低了18.16%, 具有更高的成像质量。该优化算法具备优化大孔径数目阵列的能力, 对于射电波段望远镜阵列的优化设计亦有一定的参考意义。

A merit function based on modified spatial frequency domain(UV) sampling method is proposed,which can be used to optimize the geometny of long baseline astronomy optical interferometer telescope array. The UV region to be sampled is firstly divided in both radial and rotational directions, then the number and density of UV sampling points of each segment are calculated. The deviation of UV sampling point density distribution from the ideal Gaussian distribution is taken as the merit function value. The genetic algorithm is used as the optimization algorithm, due to its global convergence capability which can reduce the dependence on initial array. A 6 apertures telescope array was optimized with the proposed merit function using genetic algorithm. Moreover, the optimized array(Array-6 array) was compared with the CHARA array. Analysis results show that the Array-6 array UV sampling points distribution in the radial direction is intensive in low frequencies and continuous, which is beneficial to the reconstruction of observation target contour and structure. The binary star observation and image reconstruction simulations show that the array optimized using the proposed merit function has better imaging performance, compared with the CHARA array. The error of reconstructed image using Array-6 is 21.34, which is 18.16% smaller than the error of reconstructed image using CHARA. Additional, the proposed merit function can be used to optimize arrays with large aperture numbers, so it also has a large application prospect for the optimal design of the radio-band telescope array.