Detectability of low-level broad-band signals using adaptive matched-fieldprocessing with vertical aperture arrays

Alerted detection of low-level broad-band signals using adaptive matched-fi eld processing (MFP) is illustrated in results from a shallow-water experim ent carried out 12 km west of Point Loma, CAI in 200-m water of complex bat hymetry, A 118-m vertical line array was deployed next to an identical line array tilted at 45 degrees. Array gain and signal excess for each of the a rrays with linear and adaptive broad-band MFP is measured and compared usin g a low-level(118 dB//1 mu Pa-2/Hz) broad-band signal from a towed source. Surface/submerged classification was achieved at the minimum detectable lev el due to the depth resolution obtained with MFP. The results are compared qualitiatively with adaptive plane-wave beamforming on a horizontal Line ar ray deployed nearby.