False alarm control and self-masking avoidance by a biparametric clutter map in a mixed interference environment

In the context of airport surface traffic surveillance through high resolution radars, an appropriate model for clutter or target backscattering is the log-normal. Because of the spatial non-homogeneity of clutter, the detection problem is better approached by the use of clutter maps. A biparametric clutter map is proposed and its performance is investigated, considering the effect of A/D conversion and an interference environment where clutter and noise may be of comparable intensity. A CFAR condition is attained when either clutter or noise dominates, and the increase of the false alarm rate is limited to well under one order of magnitude when clutter and noise have comparable power. Self-masking is avoided by the combined use of input limiting and threshold locking: the detectability loss due to self-masking is less than 4 dB in the case of clutter dominance and under 2 dB in the case of noise dominance