M.Sc Thesis


M.Sc StudentYehezkel Karo Itay
SubjectSource Localization with Feedback Beamforming
DepartmentDepartment of Electrical and Computer Engineering
Supervisors PROF. Israel Cohen
DR. Gregory Dvorkind
Full Thesis textFull thesis text - English Version


Abstract

Target localization using array processing is a highly active research field, utilized by a wide variety of applications.


Several approaches to localization are to be found. The oldest and most basic approach is beamforming in which the arena is constantly scanned in search for objects of interest where the spatial response of the array is called the beampattern.


Focusing on the beamforming approach, specifically on the beampattern itself, the analogy between the spatial response (beampattern) of uniform linear array (ULA) and the frequency response of finite impulse response (FIR) filters is well known.


In this work, motivated by the known efficiency-related advantages of infinite impulse response (IIR) over their FIR counterparts, we search for the spatial version of the IIR architecture.


It turns out that by merely integrating a transmitter to an array (not necessarily ULA), a controllable spatial loop is generated, mathematically analogous to an IIR filter. This architecture is called the “feedback beamformer”. Performance analysis confirms that an infinite (under ideal scenarios) improvement is achievable which may be interpreted as a virtual increase of the array’s aperture.


We find that the feedback beamformer is sensitive to the target’s range, where the high sensitivity is closely related to the high carrier frequencies in typical applications. We then present a more sophisticated “dual frequency feedback beamformer”, using the same resources, which extracts the spatial information from the frequency gap. This architecture features high directivity beamforming, with high performance also in low signal to noise (SNR) and low range sensitivity.