Automatic focusing of an Applebaum array

摘要

The effect of a finite distance of the signal source on the performance of an Applebaum array has been studied extensively in the literature. It has been concluded that unless the Applebaum Array is focused at the exact source location, the degradation of the output signal-to-noise ratio becomes unacceptable. The Automatic focusing technique (AFT) developed by the author for long wavelength imaging systems is used here to focus the Applebaum array at unknown source location. Thereafter, the far-field steering vector can be used successfully to form a beam towards the desired signal while suppressing the interference. In addition, substantial improvements in data processing have been achieved through the use of a partial convolution in the frequency domain. Furthermore, it is demonstrated that only half of the frequency spectrum can be used with negligible loss in signal-to-noise ratio and therefore, this procedure provides substantial reductions in data acquisition required by the AFT.