Accession Number : ADA254418


Title :   Adaptive Array Processing in Uncertain Inhomogeneous Media


Descriptive Note : Annual technical rept. 1 May 1991-30 Apr 1992,


Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS


Personal Author(s) : Oppenehim, Alan ; Baggeroer, Arthur


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a254418.pdf


Report Date : 18 Aug 1992


Pagination or Media Count : 15


Abstract : Adaptive array processing algorithms have achieved widespread use because they are very effective at rejecting unwanted signals (i.e., controlling sidelobe levels) and in general have very good resolution (i.e., have narrow mainlobes). However, many adaptive high-resolution array processing algorithms suffer a significant degradation in performance in the presence of environmental mismatch. This sensitivity to environmental mismatch is of particular concern in problems such as long-range acoustic array processing in the ocean where the array processor's knowledge of the propagation characteristics of the ocean is imperfect. An Adaptive Minmax Matched Field Processor has been developed which combines adaptive matched field processing and minmax approximation techniques to achieve the effective interference rejection characteristic of adaptive processors while limiting the sensitivity of the processor to environmental mismatch. The derivation of the algorithm is carried out within the framework of minmax signal processing. The optimal array weights are those which minimize the maximum conditional mean squared estimation error at the output of a linear- weight-and-sum beamformer. The error is conditioned on the propagation characteristics of the environment and the maximum is evaluated over the range of environmental conditions in which the processor is expected to operate.


Descriptors :   *SIGNAL PROCESSING , *ARRAYS , *ABSTRACTS , PROCESSING , MEDIA , WORK


Subject Categories : Information Science
      Electrical and Electronic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE