Clutter Reduction in Detecting Trapped Human Respiration Under Rubble for FMCW Radar System

Abstract

Detecting human respiration under rubble using a radar system causes an attenuation effect and generates additional signals beyond the target. In addition, the rubble can cause detection errors caused by the clutter from the surface and some reflections of objects under the rubble. Therefore, clutter reduction of the surface and other objects under the rubble is necessary. The identification of clutter signals originating from the wall surface performs by a method whose results uses to reduce the beat frequency arising from wall obstructions. Furthermore, that method combines with a phase detection method that extracts the Doppler response of human respiration activity. Meanwhile, reducing the clutter that comes from other reflections under the rubble is done with the proposed method, namely weighting process method. Clutter reduction aims to increase the Signal-to-Clutter Ratio (SCR) value. Laboratory experiment performed in this study used a Frequency Modulated Continuous Wave (FMCW) radar system which working at frequency of 24 GHz with a bandwidth of 200 MHz. The clutter reduction results show the extraction of respiration patterns and human position under the rubble. The obtained result using weighting process method able to increasing the SCR value approximately 10 dB, and the proposed method applies to this experimental condition.