基于非均匀周期采样的傅里叶望远镜时域信号采集方法

为了在低信噪比条件下清晰重构深空暗弱目标,提出了一种基于非均匀周期采样（NUPS）的傅里叶望远镜（FT）时域信号采集方法。对提出的方法进行了模拟实验并与均匀采样方法重构的图像进行了对比。基于NUPS方法,用1 MHz和5 MHz的采样频率分别采集100个点,对两个序列信号分别进行快速傅里叶变换,并对关心频率信息进行平均;传统的均匀采样方法则分别用1 MHz和5 MHz的采样频率采集200个点,再进行解调平均。对比结果显示：当信噪比（SNR）为50时,本文重构图像与衍射极限图像的斯托里尔比（Strehl）相比原方法提升了0.03,SNR为20时,Strehl比为0.531 1,较均匀采样提高了0.223 3。实验结果表明：NUPS方法在低信噪比条件下成像质量较高,可降低对激光功率的要求,为FT工程系统的实施奠定了技术基础。

Time region signal collecting method of Fourier telescopy based on non-uniform periodically sampling

In order to clearly reconstruct nal to Noise（SNR） , a new time domain targets in a dim and deep space under the condition of the Lower Sig- signal acquisition method of Fourier Telescopy（FT） based on Non-u- niform Periodic Sampling （NUPS） was proposed. The simulation experiments on the proposed method were performed and the reconstructed images by NUPS method and traditional uniform sample method were com- pared. With the NUPS method, 100 points were respectively collected at the sampling frequency 1 MHz and 5 MHz. Then the signals of two sequences were respectively fast Fourier transformed and the concern frequen- cy information was averaged. With traditional uniform sampling methods, 200 points were collected at 1 MHz and 5 MHz sampling frequency and then demodulated average was developed. Compared results show that the Strehl ratio of reconstructed image with diffraction-limited image is enhanced 0. 03 compared to the original method when SNR is 50, and the Strehl ratio is 0. 531 1 that is improved 0. 223 3 compared with uniform sam- pling when SNR is 20. Obviously, imaging quality is improved by the NUPS method under conditions of low SNRs, thus the laser power is reduced. The NUPS lays the technical foundation for the implementation of the FT engineering system.