Performance improvement on human detection system around detached house using UHF band transmitters

The authors proposed original human detection system around detached houses using UHF band transmitters. This paper newly studies installation positions of the transmitting and receiving antennas in the system to improve the detection performances. In the conventional system, there was a line-of-sight (LOS) path between transmitting and receiving antenna, and the detection probability was relatively low because of a strong direct radio wave. So in this study, the installation positions of both antennas are arranged to have non-LOS path between them to reduce the level of the direct wave and make a multipath-rich propagation environment. Based on the measurement using 400 MHz and 800 MHz band radio waves, this paper evaluates the detection probability of the systems in LOS and non-LOS cases. From the measurement results, it was confirmed that detection probability in the non-LOS case was over 70 % in average and was higher than that in the LOS case. And in the non-LOS case, only 2 sec monitoring time was required to detect human motion around the detached house with detection probability over 99 %.