Signal-to-noise ratio analysis in the joint time-frequency domain for ISAR imaging

Chen recently presented an ISAR imaging technique using the joint time-frequency analysis (JTFA), which has been shown having a better performance for maneuvering targets over the conventional Fourier transform method. It is because the frequencies of the radar returns of the maneuvering targets are time-varying and JTFA is a technique that is suitable for such signals. It is also known that JTFA concentrates a signal, such as a chirp, while spreads noise. In this paper, we study the signal-to-noise ratio (SNR) in the ISAR imaging using the JTFA. We show that the SNR increases in the joint TF domain over the one in the time or the frequency domain alone both theoretically and numerically. This shows another advantage of the JTFA technique for the ISAR imaging.