Receiver array ground penetrating radar imaging

Ground Penetrating Radar is considered a promising technology for the development of sensors for landmine detection. But if we want 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 crossline 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, we propose to use a physical array of receiver antennas arranged in the crossline direction. We 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 we have modeled the scattering by a point scatterer for an array of receivers with different offsets. We show that we 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 crossline sampling does not influence the resolution in the inline directions. Fast acquisition can thus be obtained for the price of using multichannel data acquisition.