Apply super-SVA to Stepped-frequency chirp signal processing based on dechirp method

Stepped-frequency chirp signal (SFCS) is an important signal form used for high-resolution radar. It contains several sub-chirp signals with stepped carrier frequency and can be synthesized to a wide-band chirp signal. Dechip method is a quick, effective method to process SFCS, it synthesizes the sub-pulses of SFCS in time-domain. The usual design rule of SFCS is the frequency step (¿f) must be less than the bandwidth of sub-chirp (B_m). If ¿f > B_m, the synthesized signal will have gaps, which leading to grating lobes in radar image. Here we proposed an algorithm by using Super-SVA to extrapolate each sub-pulse so as to fill the gaps and depress grating lobes. Without the restriction of ¿f < B_m, it will be very helpful for using less sub-chirps to obtain higher resolution and reducing the influence of target motion on the quality of synthesized signal. We presented simulations to verify the proposed algorithm. Furthermore the results imply that super-SVA can not only be used for frequency-domain extrapolation, but also time-domain extrapolation of chirp signal.