electronic beam control
active phase antenna grid
Yu.N. Guskov, V.I. Moybenko
The article examines the feasibility of using adaptive antenna grids based on APA technology for making the helicopter radar system. The use of helicopter radar is hindered by the low resolution in the real beam mode – the radar reliably detects only moving objects. The resolution up to the bandwidth is not enough for the distinction of objects, even for the detection of a still object on a forest background in a real beam mode it is necessary to raise the resolution. The search of targets in a natural environment for military purposes requires still higher resolution.
The use of adaptive antenna grids with multi-channel reception system is the most effective way of raising resolution in a real beam mode - in this case it is possible to increase the resolution approximately up to 5-6 timefold. By moving the onboard helicopter radar 3 meter sideways and using the adaptive antenna grid algorithm along with the synthesized aperture mode, it’s possible to achieve the azimuth resolution of object on 6 km distance away – up to 8 meter in a centimeter range, up to 3 meter in 8-millimeter range and up to 1 meter in 3-millimeter range. Radar with APA is a modern multi-channel systems, which are already made in a centimeter range.
There are two important differences between helicopter APA radar and fighter aircraft APA radar. First, the multi-channel reception system is necessary. Secondly, APA with electronic beam control in two planes is optional - the use a horizontal APA ruler with a mirror and mechanical drive in a vertical plane is enough for observation of earth surface. Such a ruler will have ten times less number of transmitter modules and will be cheaper than fighter aircraft APA radar.
Three-centimeter range helicopter radar with a ruler APA in azimuth plane and mechanical drive in a vertical plane, with multi-channel reception system, in a real-beam mode could provide the detection of still objects not worse than 8-millimeter range radar without APA. Therefore the use of APA technology is rational even for cheap helicopter radar.