Distinguishing Early-Time Responses Using Short-Time Half Fourier Transform

Overlapping echoes in multitarget radar sensing pose challenges for accurate detection. Specifically, late-time responses often obscure subsequent weak early-time responses. This letter proposes a short-time half Fourier transform (STHFT) method to address this. The method introduces a short-time windowed half Fourier transform (HFT) to analyze the local phase evolution, enabling accurate separation and timing estimation of early-time responses from different targets. Experiments demonstrate that the STHFT can effectively suppress aliasing in late-time responses of multitarget systems and reduce mutual interference between early-time responses in the global HFT. Furthermore, STHFT maintains a certain level of sensing accuracy and robustness even in noisy environments, which is beneficial for achieving multitarget ranging and high-precision spatial positioning in complex electromagnetic environments.