Receiver array ground penetrating radar imaging

Ground penetrating radar is considered a promising technology for the development of sensors for landmine detection. To obtain a three-dimensional image of the shallow subsurface, A-scans have to be acquired over a two-dimensional area. The spacing between A-scans must be small in order to avoid spatial aliasing and to obtain high resolution images. Hence, when carrying out data acquisition along lines, B-scans have to be repeated with a small cross-line distance as well, which is time-consuming and error-prone to accurate positioning. As an alternative to using the bi-static radar set-up, with a single source and receiver antenna, the authors propose to use a physical array of receiver antennas arranged in the cross-line direction. The authors try to make a three-dimensional image of the subsurface by measuring a single line of multi-channel data with the receiver array. The main advantage is that acquisition is fast and less dependent on accurate positioning in the two-dimensional plane. To validate this measurement strategy the authors have modeled the scattering by a point scatterer for an array of receivers with different offsets. The authors show that they can combine the data of the different receivers to obtain an image of the subsurface which gives adequate information on the position of the object both in the inline, cross-line and depth direction. It appears that the absence of cross-line sampling does not influence the resolution in the inline directions. Fast acquisition can thus be obtained for the price of using multichannel data acquisition.