Nyquist折叠接收结构基于压缩采样理论，提供了超宽频段下的稀疏信号低复杂度接收方法。项目组前期初步开展了基于NYFR的常规雷达信号分析与处理方法研究，但是针对超宽带复杂调制雷达信号低信噪比下的信号检测与参数估计、无混叠Nyquist区域的本振及其参数的优化模型选择、多通道NYFR的联合信号检测与参数估计、多信号高保真恢复等关键问题尚未涉及。项目基于模拟信息转换欠采样压缩感知理论，拟通过构建超宽带复杂调制雷达信号Nyquist折叠展开可重构新型结构，开展超宽带复杂调制雷达信号在Nyquist折叠展开结构中的机理研究、特性分析、欠采样下的稀疏信号检测和参数估计、基于压缩感知和信号结构特征的信息重构、多信号高保真恢复等关键问题的理论研究、算法构建及性能分析和相关应用工作；建立新的信号处理模型、基本理论和方法，对突破超宽带非合作信号对抗技术瓶颈是一项具有重要理论价值和实际意义的创新性工作。

Nyquist folding receiver (NYFR) is a structure based on the compressive sampling (CS) theory which provides a low-complexity receiving method for sparse signal in ultrawideband environment. This project has preliminarily studied some common radar signal analyzing and processing methods based on NYFR, but the key problems including detection and parameter estimation of ultrawideband complicated modeluated radar signals in low signal-to-noise ratio, the selections of local oscillators and their optimal parameters for the non-overlapping regions, the joint detection and estimation of the multi-channel NYFR structure and the high fidelity recovery of multiple signals have not been studied yet. Based on the analog-to-information converter undersampling CS theory, this project will build a novel Nyquist folding and unfolding reconfigurable structure and method for the ultrawideband complicated modulated radar signals. and based on the structures, do researches on problems inlcuding the mechanism and characteristics of ultrawideband complicated modeluated radar signals, detection and parameter estimation of undersampled sparse signals, information reconstruction based on CS theory and signal structure characters, and high fidelity recovery of multiple signals etc. To solve the above mentioned problems, the theory research and algorithms designment including their performance analysis and related applicationsour group will be mainly concentrated in this project. Building the novel signal processing models, fundamental theories and methods will be a novel work which has both theoretical signifiance and practical value to break through the bottleneck of ultrawideband non-cooperative signal countermeasure techniques.