For demonstration of the surveying efficiency of RASCAN-4 radar, a model of wall was made. The wall mockup was presented by a packet consisting of fifteen 1 m by 1.2 m plasterboards. The packet was 22.5 cm thick in the aggregate, and there were different objects placed between the layers. Two metal wires and seven 25-mm coins presented the objects under consideration. One of the coins was placed under the left-hand wire and the other one was under the right-hand wire. Besides, a 3 cm by 3 cm square opening was made in the second plasterboards and the opening's depth was identical to the board thickness, i.e. 1.5 cm.

The arrangement of the objects within the wall mockup is presented in the Figure. The size of the shadowed surface on the diagram is equal to 0.6 m by 0.6 m. The figure placed at each of the objects states the ordinal number of a layer, counted from above, under which this object is located, i.e. the object No. 2 lays between the 2nd and 3rd layers of dry plaster. A recess was made in the 3rd and 4th layers where a pistol mockup was placed; its barrel length is equal to 13.5 cm and its handle length equals 9.7 cm. A grid was plotted on the diagram for convenience. The grid spacing equals 3 cm.

Figures below shows microwave images of the mockup part enclosed by a dotted line. This figure presents two microwave images, which have been obtained at the parallel (left image) and cross (right image) polarizations of the received and transmitted radar signals. Wires, seven coins and the opening in plasterboard are observed in the image. Note that both coins placed before and behind the wire are seen very well. The possibility of the observation of an object located behind another object in its shadow is related to the differences in the phases of signals reflected from objects located at different depths. By changing the frequency of a sounding signal, we can reduce the contrast of a nearby object and enhance the contrast of an object positioned at a greater depth behind the former one.

Here you can see animated image of the same mockup part (2 MB).

Figure below shows the microwave image of the part of the mockup enclosed by a dash-dot line. The pistol outline is seen in this image.