Digital beam forming for sonar systems

Recent Trend and Advance of Synthetic Aperture Radar with Selected Topics

“…DBF is a technique of producing multiple beams by dividing an antenna into multiple sub-apertures, and digitally processing the signals of each sub-apertures independently [187]. The technique has been used in HF radars, sonar, and communication systems [188][189][190][191]; the idea of multiple-beam wide-swath SAR has also been suggested since 1980s [192][193][194]. Currently, DBF is considered to be a promising concept for future spaceborne SAR systems for solving the trade-off between the swath width and spatial resolution due to the limitation imposed by range and azimuth ambiguities.…”

Digital Signal Processing Applied to the Modernization Of Polish Navy Sonars

“…Since then digital signal processing methods have been continuously improved to keep up with the demands of the new developments [5,6,10,15,16,41,54,63]. Equipped with digital signal processing, sonars are now capable of delivering a wide range of new functions which were not available or difficult to achieve in the analogue technology or early digital technology, respectively.…”

“…The basic tasks of digital signal processing in sonar systems include spatial filtering, also known as beam-forming, spectral analysis, matched filtration and correlation analysis [5,6,10,15,16,41,54,63]. The next sub-sections are concerned with how these tasks are completed in the modernized sonars.…”

“…DSP operations can be significantly accelerated by applying the FFT algorithm to spatial frequencies [5,6,15,54]. Because the application of the FFT algorithm involves a linear distribution of phase shifts, the result is a nonlinear distribution of beam deflection angles.…”

“…Beam-forming in a cylindrical array involves compensating for signal delays. They are the result of the different distances covered by waves coming to the array columns in a sector [5,41,54]. Unlike in the above described method, the modernized sonar with cylindrical array has a higher number of beams.…”