Array-Based Ultrawideband through-Wall Radar: Prediction and Assessment of Real Radar Abilities

Abstract

This paper deals with a new through-the-wall (TTW) radar demonstrator for the detection and the localisation of people in a room (in a noncooperative way) with the radar situated outside but in the vicinity of the first wall. After modelling the propagation through various walls and quantifying the backscattering by the human body, an analysis of the technical considerations which aims at defining the radar design is presented. Finally, an ultrawideband (UWB) frequency modulated continuous wave (FMCW) radar is proposed, designed, and implemented. Some representative trials show that this radar is able to localise and track moving people behind a wall in real time.

Through-The-Wall Detection With Gated FMCW Signals Using Optimized Patch-Like and Vivaldi Antennas

“…The stand-off distance of the wall from the probes is 250 cm. A 5 cm air gap is placed in the middle of the wall to make it more realistic, as well as more challenging for the detection of the targets as this structure can trap electromagnetic waves, thus increasing the duration of the wall reflection signal [31]. Fig.…”

Shadow Effect Mitigation in Indication of Moving Human Behind Wall via MIMO TWIR

“…3, herein, CF is used to correct the BP image I(x, y) = CF(x, y) · BP(x, y). (9) CF can well retain the human target with only limited mitigation of the shadow ghost and can also suppress other lowcoherence features such as sidelobes and multipath with finer azimuth resolution.…”

Frequency-Modulated Interrupted Continuous Wave as Wall Removal Technique in Through-the-Wall Imaging

“…Different UWB waveforms have been used in these systems, including short impulses [2][3][4], noise [5] and pseudo-noise waveforms based on M-sequences [6], stepped frequency continuous wave (SFCW) signals [7][8][9], and frequency modulated continuous wave (FMCW) signals [10][11][12][13][14][15].…”

“…Walls with air gaps or hollow structures are especially challenging, since they tend to trap the electromagnetic waves as if in resonant cavities, making the duration of the wall reflection signals far longer than the physical thickness, thus overshadowing targets close to the interior wall [11,16]. The presence of strong undesired signals limits the dynamic range of the TTWD system and increase the possibility of saturating and blocking the receiver [12].…”

“…Since the wall is physically closer to the radar system in comparison with the targets, its contribution appears at lower frequency components, which can therefore be filtered out with a suitable band-pass filter integrated at the receiver [10][11][12][13][14][15]. In [15] for instance, coherent change detection and band-pass filtering are combined on a vehicle-mounted system.…”