On array design for matched-field processing

Abstract

Conventional plane-wave beamforming array design guidelines are motivated by the desire to obtain particular beampattern characteristics, such as main lobe width and side lobe levels. These design guidelines are appropriate for arrays employed for beamforming, where a plane-wave signal model is utilized to derive both the array design parameters and the beamforming algorithm. However, matched-field processing utilizes full-field acoustic propagation models to exploit the complexities of ocean acoustic propagation. As a result, there may be more appropriate design guidelines for arrays employed for matched-field processing. In this paper, general guidelines for matched-field processing array design utilizing a normal mode propagation model are proposed. Various line array configurations are evaluated with respect to source localization performance, and the results suggest that arrays designed for matched-field processing should provide a unique representation of each propagating mode along the extent of the array. Further, the empirical analyses support the guidelines suggested by the theoretical analyses and show that arrays which are far from meeting conventional beamforming array design requirements may be more than sufficient for matched-field processing.

Statistical description of matched field processing ambiguity surfaces

“…HLA and VLA geometries can be directly compared using metrics that describe the extent to which the MCM is diagonally dominant. 7,8 MFP ambiguity surfaces are characterized by a complicated set of local maxima and minima that shift with source location and environmental parameters. As a result, they have often been described by statistical measures such as peak-to-average sidelobe ratio and deflection index.…”

Matched-field Source Localization with a Mobile Short Horizontal Linear Array in Offshore Shallow Water

“…If the source is assumed to be at the other bearing, then the effective length of the array is shorter, and elements are more closely spaced. The relationship between the actual and effective array lengths and respective sensor positions is a function of the source range and it may be determined through trigonometric relationships (Tantum, Nolte, 2000). Moreover, the depth of the horizontal linear array does impact on the source localization performance attained by MFP techniques (Tolstoy, 1993; Tantum, Nolte, 2000).…”

“…However, the platform also limits the array length to less than ten meters. In MFP theory, for the vertical linear array, increasing the array length to span more of the water column can significantly improve MFP sidelobe reduction and peak resolution, and the horizontal linear array usually requires a much longer array length than the vertical array for the same localization performance (Tolstoy, 1993;Tantum, Nolte, 2000). The short arrays can hardly obtain sufficient spatial gain.…”

On marine mammal acoustic detection performance bounds

“…(23). According to the derivation in Appendix A, the square of separation parameter, or the detection index is…”

“…It is a challenge for the underwater acoustic communication systems. Research has been done to evaluate the uncertainty of environmental parameters to source localization [21], [22], [23], and detection in the time domain [24], [25]. In this paper, we will evaluate the influence of the uncertainty of the sound speed profile on detection in the time-frequency plane.…”