Application of Equivalent-Time Sampling Combined with Real-Time Sampling in UWB Through-Wall Imaging Radar

摘要

Experiments show that ultra-wideband (UWB) through-wall imaging radar enables good penetration capabilities operating in the frequency range 0.3GHz to 3GHz. According to Shannon sampling theorem, signal acquisition unit only be able to acquire a signal with at least 6GS/s sampling frequency utilizing real-time sampling electronics. It is difficult to find such A/D converter chip in practice. Taking it into account that ultra-wideband through-wall imaging radar transmits signal repeatedly, this paper proposes a method of applying equivalent-time sampling combined with real-time sampling in UWB radar to acquire the echo signal. An ultra-wideband through-wall imaging radar which embeds a PC104 as its main control unit and a FPGA as its timing controller is developed based on this method. The application shows that the ultra-wideband signal can be sampled and recovered with the use of this method.