Analysis of MIMO Transceiver Signal in Through-The-Wall Imaging Under Multiple Wall Reflection

Abstract

Through-the-wall imaging is a recent topic of interest in the field of surveillance, military operations and rescue operations. Through-the-wall radar imaging (TWR) systems enable determination of the building layout and the sensing of objects and/or humans behind obstacles. As such, they are indispensable for situational awareness in a wide range of civilian and military applications, including surveillance and reconnaissance, hostage rescue, and detection of survivors trapped in rubble in case of natural disasters.
The multiple-input multiple-output (MIMO) operation, which was successfully applied to wireless communications, has been introduced in radar as well. A MIMO radar is a system, which employs multiple transceivers in transmitting mode for simultaneously transmitting diverse (possibly linearly independent) waveforms and by utilizing multiple transceivers in receiving mode to receive the reflected signals from the region of interest. This work focuses on analysis of the received transceiver signals, which are affected by the wall propagation and multiple reflections from the wall present inside the region of interest.
The region of interest can be divided into small regions (pixels), spread in cross range and down range, where absence or presence of a target is indicated by the intensity of the darkest pixel in the resulting image. Multiple copies of the transmitted signal are received on the receiver, which can be exploited to re-map the returns on the appropriate pixel. This work tests the above concept, considering assumed transceiver configuration and the geometry of region of interest, with a few number of multiple reflected signals from walls.