论文部分内容阅读
准确理解大气湍流扰动相位对光束传输特性的影响机制,并以此为基础发展有效的相位误差补偿算法是实现合成孔径激光雷达(SAL)高质量成像的关键之一。从激光光束的相位结构函数入手,提出了一种新的大气湍流相位屏产生方法——结构函数法,建立了满足Kolmogorov统计规律的大气湍流数值模型,计算了不同强度湍流作用下机载SAL的成像结果。通过将其与秩一相位估计法联合使用,克服了秩一法对初始值敏感的缺点,提高了补偿算法的精度和效率。实验表明,与谱反演法相比,结构函数法的计算结果更接近于理论值,同时计算复杂度由O(N~2)降至O(N)。改进的秩一法能够较为有效地改善一定强度范围内大气湍流引起的SAL图像失真,而且补偿后图像的信噪比相比传统的秩一法提高了大约5 dB,计算时间也缩短了约30%。
To accurately understand the influence mechanism of atmospheric turbulence perturbation phase on the beam transmission characteristics and to develop an effective phase error compensation algorithm based on it is one of the keys to realize high quality imaging of synthetic aperture laser radar (SAL). Starting from the phase structure of the laser beam, a new generation method of atmospheric turbulent phase screen - structural function method is proposed. The numerical model of atmospheric turbulence satisfying the Kolmogorov statistical rule is established. The effects of turbulence on the airborne SAL Imaging results. By using it in combination with rank-one phase estimation, it overcomes the shortcoming that rank-one method is sensitive to the initial value and improves the accuracy and efficiency of the compensation algorithm. Experiments show that compared with spectral inversion method, the result of structural function method is closer to the theoretical value, and the computational complexity is reduced from O (N ~ 2) to O (N). The improved rank-one method can effectively improve the SAL image distortion caused by atmospheric turbulence within a certain intensity range, and the SNR of the compensated image is improved by about 5 dB compared with the traditional rank-one method, and the calculation time is shortened by about 30 %.