Preprocessing for Adaptive Spatial Filtering in Ground-Based Rotating Radar Systems

An effective scheme for spatio-temporal processing with ground-based rotating radars consists in making adaptive spatial filtering, with frequent updates, followed by temporal processing. In presence of jamming and clutter, spatial processing first filters jammers, whereas temporal processing then filters clutter. However, starting by making a spatial adaptive processing requires to dispose of jamming + noise alone reference. But as clutter has not been filtered yet, it may be present in estimation data with stronger power than that of jammers. Therefore, the estimation of the jammer correlation matrix will be degraded resulting in a fall of performances of spatial processing. In this paper, it is first proposed to use a preprocessing before spatial filtering. The objective of this preprocessing is to reduce clutter power in the estimation samples used to compute adaptive spatial filters and thus improve the efficiency of jamming filtering. Then, a performance study of this preprocessing in terms of clutter power reduction is made, aiming at quantifying both the influence of antenna rotation and clutter decorrelation