BEAM POINTING ERRORS OF PHASED-ARRAYS FOR DIGITAL SWITCHED BEAM ACOUSTIC RADARS

Phased array antennas and corresponding driving electronics units have been introduced in Atmospheric Acoustic probing. Using modern micropr ocessor systems in conjunction with suitable digital electronics, it i s possible to implement an acoustic probing system, with full beam swi tching capabilities. The radiation pattern of a planar M x N phased ar ray acoustic radar equipped with digital phase shifting circuits for t he beam switching, is examined and all the necessary formulas are pres ented. For a given accuracy of phase quantization, the set of beam poi nting directions which can be achieved without deterioration, due to t his quantization, is computed and diagrams showing the mapping of the available beam pointing directions throughout space are presented. The relation between the cardinal number of this set of directions and th e accuracy of the phase quantization is also presented. The beam point ing errors, due to the accuracy of the phase quantization and the diss imilarities among the array's elements are analysed using simulation t echniques.