  The through-the-wall human being detection and localization in the complex
environments by using the radar system has many possible applications such as
for law enforcement, and search and rescue missions in disaster-stricken areas.
This paper discusses the experimental study of ultra-wideband impulse radar for
obscured human respiration detection through spectrum analysis. We investigate
the effect of the range of human-wall and radar-wall to the peak factor value
of human respiration sign power spectrum. This result will be useful as a
reference for analyzing the possibility of the sign to be detected by the radar
with respect to the distance from both sides. According to the experimental
results, longer both distance increases gradually the peak factor value.
However, the peak became narrower. Besides, at a very short distance between
areas and walls, the peak factor became very small because of the strong
reflection of both objects. Therefore, an adaptive threshold technique and
background suppression are needed in order to maintain the detection
performance against any possible conditions.
