Design of digital receiver for ISAR radar based on compressed sampling

This paper introduce the theory of Compressed Sensing (CS) into the design of intermediate frequency (IF) digital receiver for wideband ISAR radar. First, a redundant dictionary is presented where the IF echo of linear frequency modulated (LFM) radar can be represented sparsely. Then we utilize random sampling and design a novel architecture of IF digital receiver, making it possible to digitize the wideband IF signal using a commercial off-the-shelf analog-to-digital converter (ADC) with sub-Nyquist sample rate. The Smooth ℓ₀ (SL0) algorithm is employed to reconstruct range profile from sub-sampled results, while 2D SL0 algorithm is improved to reconstruct the ISAR image of target. Compared with the traditional band-pass digital receiver, equivalent result of matched filter and ISAR imaging can be obtained using much fewer samples in our system. A series of simulation validates the design and demonstrate the feasibility of our sub-Nyquist sampling and reconstructing algorithm.