Bistatic extension for coherent MMW-ISAR-Imaging of objects and humans

Abstract

Abstract. We present a bistatic extension of a broadband monostatic FMCW Radar working in the Millimetre-Wave (MMW) region and its bistatic imaging properties used for imaging purposes. Due to the different perspective of a bistatic setup compared to a monostatic one, additional information can be obtained.A wide bandwidth of approx. 10 GHz is used for the task of high resolution imaging as it could be used for the detection of threats at a person's body in security-sensitive environments. Since MMWs propagate easily through common clothing, it is feasible to image objects like concealed weapons worn under the clothing. MMW-Imaging of humans is one possibility to enhance the capabilities of nowadays security checkpoints, e.g. at airports.

Comparative Description of Setups for MMW-Imaging of Persons

“…For this purpose a FMCW-radar sensor operating in W -band is used. The system itself is similar to the one described in [1] or [2] except that the bandwidth covers the whole W -band. Relevant parameters of the setup are summed up in Table I.…”

A Study on Millimeter-Wave Imaging of Concealed Objects: Application Using Back-Projection Algorithm

“…For this purpose,various researchers have demonstrated both passive and active imaging systems [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Passive imaging systems are based on the detection of natural radiation from the targets and reflection from the environment [9][10][11][12] and hence mostly limited to outdoor missions.…”

“…Besides, the lack of range information in the provided two-dimensional (2D) images puts an additional limit on the detection problem. On the other hand, active imaging systems [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] exploit various radar systems giving rise to indoor operation as well as sharp range resolving ability. Hence, the position and shape of the concealed objects can be attained from the produced threedimensional (3D) images.…”

“…The active imaging, though, faces some challenges in fulfilling the vital requirements such as fast scanning of the whole body from all aspects and accurate imaging of the acquired near-field data. For this reason, various studies have been focused on the different scanning set-ups along with the consideration of the appropriate near-field reconstruction algorithms [21][22][23][24][25][26][27]. In [21], Sheen et al, originally adapted planar scanning aperture and 3D range migration algorithm (RMA) for imaging the human body.…”

“…Although RMA seems to be the conventional imaging technique, it comes with a difficult implementation for the bistatic configuration [29] of which usage may be favorable to increase the detection capabilities. As an alternative, the back-projection algorithm that is directly applicable to any data collection geometry has been recently employed in a few studies of the concealed object detection problem [25][26][27]. In these studies, both the monostatic [25] and the bistatic [26] imaging performances were investigated for the cylindrical reconstruction surface.…”