Array Signal Processing on Distributed Acoustic Sensing Data: Directivity Effects in Slowness Space

Distributed Acoustic Sensing (DAS) involves the transmission of laser pulses along a fiber-optic cable. These are backscattered at fiber inhomogeneities and again detected by same interrogator unit that emits pulses. Elastic deformation causes phase shifts in which converted to spatially averaged strain measurements, typically regular intervals. DAS systems provide potential employ array processing algorithms. However, there certain differences between conventional sensors. While seismic sensors record directional particle displacement, velocity, or acceleration, axial is inherently proportional spatial gradient cable displacement. therefore insensitive broadside for example, P-waves. In classical delay-and-sum beamforming, response function far-field on horizontal slowness (or wavenumber) grid. geometrically non-linear layouts, angle wavefront varies, requiring analysis steered varies with direction arrival. This contrasts traditional given terms difference arrival steering. paper provides framework estimation accounting also directivity gauge-length averaging – hereby demonstrating applicability seismology assess design aspects. It bridges gap theory frameworks communities, facilitating increased employment as array, while providing building blocks development tools.