Threshold control for a millimetre-wave miniradar: biparametric vs. monoparametric clutter maps

Surface movement radar employed in surface movement guidance and control systems (SMGCS) have to detect and locate any object on the airport surface that may adversely affect the safety of operations. The objects of interest belong to a variety of categories (e.g. aircraft, vehicles, movable staircases, suitcases), as well as the clutter in which they are embedded (the concrete/asphalt of the tracks, the grass surrounding them, rain). In addition, clutter may not be the dominant interference factor: in the general case the interfering environment will be made up of a mixture of clutter and of Gaussian noise. As the resulting interfering background will be time-varying too, the adaptive control of false alarms is a much needed feature of the radar signal processor. Traditional cell-averaging CFAR techniques cannot be adopted here, because of the spatial non-homogeneity of clutter. A clutter map approach (also known as temporal adaptive thresholding or scan-by-scan averaging) is therefore preferred. An already proposed detection scheme based on this approach is the so-called monoparametric clutter map. The limitations of this scheme are further explored; subsequently a novel processor, named the biparametric clutter map, is proposed and the performances of the two schemes are compared.