A Sub-Nyquist Radar Electronic Surveillance System

The modulated wideband converter (MWC) is well-known for a sub-Nyquist wideband sampling capability based on compressed sensing (CS) theory. In this paper, our goal is to use the MWC as a base to design a sub-Nyquist radar electronic surveillance (ES) system. Our focus is then to extend the capabilities of the previous MWC system in order to meet the challenges, i.e., a very long acquisition time, a much larger simultaneous monitoring bandwidth, and a faster digital signal processing receiver. To this end, we present a new performance analysis framework and then a new digital domain receiver. The proposed performance analysis framework will be useful in comparing signal-acquisition performance of the proposed ES system with those of other sub-Nyquist receivers, including those of the classical Nyquist rate receivers, without resorting to extensive simulations. This framework can also be used to study the complex interplays of important system parameters of MWC, such as the sampling rate, the number of parallel channels, the period of Pseudo random sequence, and thus guides us in selecting the right system dimensions and parameters for desired performance. Radar surveillance application has its inherent needs for very long acquisition time and simultaneous monitoring of very large frequency range. To meet this challenge, a fast signal recovery system needs to be developed, so that radar signal logistics can be retained and recovered from compressed samples. We have proposed a split and synthesis process in which the radar signal recovery problem over a long signal acquisition time can be divided into many small CS signal recovery problems, and the solutions for small pieces are put together later on at the end. In addition, a sub-sampling method is proposed to have the multiple measurement vector problem complete signal recovery faster without noticeable performance loss.