基于MWC压缩采样原理的被动雷达宽带数字接收机研究

Nowadays there are some bottleneck problems that contain more and more complex structure, larger and larger amounts of samples and the difficulty of cross-channel signal processing with wider and wider bandwidth design and the increase of number of channelization in traditional wideband digital receiver based on uniform channelization design in the practical applications such as passive radar and electronic reconnaissance. This MWC (Modulated Wideband Converter) model based on compressed sampling is extended to digital domain and a novel architecture of wideband digital receiver based on AIC-MWC principle is proposed in this project. By using this architecture, the spectrally sparse signal can be reconstructed without information loss, less branches compared with uniform channelization receiver are required and sub-Nyquist sampling rates may be obtained. According to the principle that the signal modulated by periodic pseudo random sequence can obtain linear combination spectrum of periodic shifted copies and all spectrum information about input signal can be contained in baseband after mixing, it is beneficial to cross-channel signal recognition. The project will deeply focus on the following issues.1) Design of wideband digital receiver structure based on MWC principle. 2) Direct intra-pulse recognition of radar signal based on compressed sampling data without complex operation about signal sparse reconstruction. 3) Study of realization technology based on FPGA platform. The final realization of the project will provide effective and intelligent solutions of signal processing for passive radar and radio reconnaissance system. It will also promote new application and development for AIC and digital receiver theory. This technology will also enforce the development of national security and national defense.

目前被动雷达、电子侦察接收等设备的宽带数字接收机大多采用均匀信道化结构，其随着接收机带宽及信道化数目的增加，采样数据量变大，系统实现也越发复杂，同时还面临复杂的跨信道信号处理等瓶颈问题。项目提出基于压缩采样的调制宽带转换（AIC-MWC）原理的全新的宽带数字接收机设计。实现将MWC理论扩展到离散领域，保证频域稀疏信号在信息不丢失条件下，用较少的采样分支数实现Sub-Nyquist采样，从而降低系统实现复杂度。由于MWC将信号固定移位的频谱做线性组合后折叠到基带，这样又有利于跨信道信号的处理。项目拟深入研究以下问题： 1）基于MWC等压缩采样理论的宽带数字接收机结构；2）基于压缩采样数据的直接雷达信号脉内识别；3）基于FPGA的宽带数字接收机实现。项目最终将为被动雷达、电子侦察等系统提供全新的宽带数字接收机解决方案；促进AIC及数字接收机理论的应用与发展；也必将促进国家安全和国防事业的发展。

针对传统的宽带数字接收机存在采样数据量庞大，系统结构复杂，且难以处理跨信道信号的问题，本课题将调制宽带转换器（MWC）结构扩展到离散数字域，构建了基于MWC的压缩采样宽带数字接收机，该接收机可以实现Sub-Nyquist采样，减少接收机系统的分支路数，并可以灵活的解决宽带信号跨信道问题。课题主要完成了三部分内容：1）完成了基于MWC压缩采样理论的宽带数字接收机结构设计理论。实现了基于伪随机循环序列调制的接收机设计，多路压缩复用压缩接收机结构设计，基于MWC的阵列结构设计，完善了压缩稀疏阵列结构。2）完成了基于压缩采样数据的直接雷达信号脉内识别。实现了基于复数信号和实数信号的频率测量算法，给出了基于阵列结构的频率和DOA估计算法，给出了针对调相、调频信号的脉内识别算法。3）实现了基于FPGA的MWC压缩数字接收机。利用FPGA验证了算法的正确性和实用性，特别是提出的基于多相结构的MWC压缩数字接收机FPGA实现方法，可满足实际工程的需求。课题构建理论和结构的同时，并提出了一系列基于压缩采样数据的信号处理算法，为该接收机的设计及PDW形成奠定了基础。项目完善了AIC及数字接收机理论，成果可为被动雷达、电子侦察等系统提供全新的宽带数字接收机解决方案，必将促进国家安全和国防事业的发展。