On theuse ofenergyconcentrating beamformers and filters fordetection ofwideband angularly spreadsignals

Slepian described thefilter thatmaximizes thein- bandenergywhileminimizing theout-of-band energy. Claus, KadotaandRomainapplied Slepian's results tospatially filter outangularly distributed interference. An important benefit of this approach isthatbothcoherent andincoherent interference canbeaccommodated. Theapproach discussed hereextends their workbydefining matrixfilters capable offiltering for a fixed angular sector, (O1,02), overa rangeoffrequencies. A detector ofscattered broadband signals arriving within(O1,02) isthenspecified. Thedetector isshowntopossess important invariances andapproximate optimality properties related to Scharf's Constant False AlarmRate(CFAR)matchedsubspace detector.