Examination of the Effect of Array Weighting Function on Radar Target Detectability

A methodology is described to assess the detectability of targets by an airborne fire control radar (FCR) operating in a medium pulse-repetition frequency (PRF) mode in the presence of strong ground clutter as a function of the transmitting and receiving antenna array weighting functions and proportion of failed array elements. It describes the radar, antenna, and clutter modelling processes and the method by which target detectability is quantified. The detectability of targets in clutter is described using a detectability map, which provides a useful means of comparing target detectability as clutter conditions change. It concludes that the best target detectability is to be achieved using those weighting functions on transmit and receive which result in the lowest average sidelobe levels but that the margins between the more highly tapered weighting functions were small. Furthermore, it concludes that target detectability degrades as the proportion of failed elements increases. A failure of 5% of the elements gave modest, though meaningful, degradations in target detectability and would therefore form a suitable upper limit.