Beamspace esprit for multi-source arrival angle estimation employing tapered windows

This paper presents two new algorithms that operate in beamspace and provide closed-form arrival angle estimates in conjunction with uniform linear arrays. The algorithms window the array data using either a cosine shaped window or a Hanning window prior to beamforming. The resulting array patterns have low sidelobe levels (peak sidelobe leve ≈ −23.5dB for cosine window, peak sidelobe level ≈ −32.3dB for Hanning window) and provide enhanced out-of-band source suppression. In contrast, the existing DFT Beamspace ESPRIT algorithm employs a rectangular window; the resulting array pattern has a peak sidelobe level of ≈ −13.5dB. The new algorithms clearly provide better out-of-band source suppression than DFT Beamspace ESPRIT. They can provide arrival angle estimates of sources in a given spatial sector without being swamped by powerful sources lying outside the sector of interest.