复杂动态环境下精细导星仪拖尾星斑复原方法

Restoration of Smeared Star Spot for Fine Guidance Sensor under Complex Dynamic Conditions

为提高动态环境下精细导星仪的质心定位精度,提出一种两步复原方法来解决因载体角运动和小幅度随机振动引起的星斑拖尾问题。根据模糊星斑两次快速傅里叶变换检测出的模糊核函数,采用约束最小二乘方滤波消除由载体角运动带来的星斑长拖尾。针对残余的载体小幅度随机振动导致的星斑模糊,将清晰星斑梯度分布先验作为正则约束对星斑粗复原结果进行迭代盲复原,并引入半二次优化算法求解非凸代价函数来提高迭代收敛速度。实验结果表明,在角速度为4000μrad/s的动态环境下,复原后的星斑已接近于高斯分布,峰值信噪比相比逆滤波复原方法及R-L复原方法分别提高了61.9%、32.9%,质心定位误差分别减小了59.9%、43.4%。

In order to improve the centroid location accuracy of fine guidance sensor in dynamic environment,a two-step restoration method is proposed to solve the problem of star spot trailing caused by angular motion of carrier and small amplitude random vibration.Constrained least squares filtering is used to eliminate the long tail of the star spot caused by the angular motion of the carrier according to the fuzzy kernel function detected by the two fast Fourier transforms of the blurred star spot.Aiming at the residual blurring caused by small amplitude random vibration of the carrier,the clear star spot gradient distribution prior is used as a regular constraint to iteratively blind restoration of the coarse restoration results.The half-quadratic optimization algorithm is introduced to solve the non-convex cost function to improve the convergence speed of the iteration.The experimental results show that the restored star spot is close to the Gauss distribution in the dynamic environment of 4000μrad/s angular velocity,and compared with the inverse filtering and R-L methods,the peak signal-to-noise ratio is 61.9%and 32.9%higher and the error of centroid location is 59.9%and 43.4%lower,respectively.