功率谱反演大气湍流随机相位屏采样方法的研究

Sampling methods of power spectral density method simulating atmospheric turbulence phase screen

从产生大气湍流随机相位屏的功率谱反演法原理出发,分析了均匀采样造成的随机相位屏大量低频信息泄漏的不足,提出利用非均匀采样方法对功率谱进行滤波产生随机相位屏.建立了非均匀采样模型,并分析比较了两种采样方法覆盖的采样频率范围和单边采样频率区域的湍流功率,理论证明了非均匀采样功率谱反演产生大气湍流随机相位屏的可行性和有效性.针对大气湍流的Kolmogorov谱,分别仿真计算了两种采样模型下功率谱反演生成的大气湍流随机相位屏.仿真结果表明,在不增加采样点和计算量条件下,非均匀采样方法生成的大气湍流随机相位屏具有丰富的低频和高频信息,有效改善了传统功率谱反演大气湍流随机相位屏时低频信息严重不足的缺陷.

Based on power spectral density method, the uniform sampling leading to the leakage of low frequency in atmosphere phase screens is analyzed. A new method - non-uniform sampling is proposed. The non-uniform sampling is modeled. The covered sampling frequency regions and the powers of single sampling region by the two sampling methods are discussed and compared. The new method proves to be effective and feasible. For the Kolmogorov spectrum of atmospheric turbulence, the numerical simulation phase screens are generated by the two sampling methods. The simulation results show that the random phase screens generated by the non-uniform sampling method under the condition of increasing neither sampling number nor computation burden, possesses rich high and low frequency information.