Improved through-wall radar imaging using modified Green\u2019s function-based multi-path exploitation method

Shuangshuang Wu,Huilin Zhou,Song Liu,Rongxing Duan

doi:10.1186/s13634-020-0660-2

Shuangshuang Wu, Huilin Zhou + Show 2 more

Open Access

https://doi.org/10.1186/s13634-020-0660-2

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Abstract

The existence of walls surrounding targets leads to multi-path return at the radar receiver, which provides additional information about the target, and thus can be exploited to strengthen the quality of through-wall radar imaging (TWRI). Based on this, a multi-path exploitation method is proposed to identify the location of the multi-path ghost. An algorithm that combining the modified Green’s function with back projection algorithm is presented to associate and map the multi-path ghosts to the location of real targets. The theoretical analysis is verified according to the simulation results obtained using gprMAX software as well as practical radar measured data, and our proposed method is shown to outperform that in conventional multi-path exploitation method (Setlur et al., IEEE Trans. Geosci. Remote Sens. 49:4021–4034, 2011).

Highlights

Through-wall radar imaging (TWRI) has attracted much attention in various fields, due to its numerous civil and military application [1,2,3,4]
In the traditional narrowband radar system, it is difficult to separate the original returned signal of target with the those caused by multi-path due to the poor range resolution and the time-delay resolution [5]
Combining with the modified Green’s function, we associated and mapped the multi-path signal to obtain the image of the real target

Summary

Introduction

Through-wall radar imaging (TWRI) has attracted much attention in various fields, due to its numerous civil and military application [1,2,3,4]. The targets of the throughwall radar are those objects that are located inside rooms surrounded by walls This leads to the superimposing of multi-path returned signals and the direct returned signal. We propose a calculation model of modified Green’s function based on the non-line-of-sight (NLoS) propagation path. Let the time-varying transmitted signal denoted by s(t), the composite received signal at the nth sensor by the superposition of the direct path and multi-path returns is given as rn(t) = A0s t − 2τA(n) +. Combining with the modified Green’s function, we associated and mapped the multi-path signal to obtain the image of the real target. Considering the effect of delay inside the wall, a modified Green’s function calculation model based on the non-line-of-sight (NLoS) propagation path is proposed.

Multi-path identification and localization

Results and discussions

Results of real measured dataset

Conclusion