D3LS STAP Approach on Wideband Signals using Uniformly Spaced Real Elements

Abstract

In this paper, Space Time Adaptive Processing (STAP) applied on wideband signals from uniformly spaced real elements using Direct Data Domain Least Squares (D 3 LS). Two antenna configurations are used: an array of dipole antenna (narrowband antenna) and an array of patch antenna (wideband antenna). A frequency transformation technique is used only for the case of narrowband antenna which transforms the steering vector at a wideband frequency to another steering vector at the desired frequency. The mutual coupling between elements will affect on the estimation of complex amplitude of Signal of Interest (SOI). It is necessary to compensate for the strong mutual coupling that exists between the real antenna elements. This is done by using coupling transformation matrix which converts the voltages that are induced at the real antenna elements to an equivalent set of voltages that will be induced by the same incident wave in uniform linear virtual array (ULVA). Then, we will apply STAP D 3 LS on the compensated voltages. Numerical simulations are done using the three main methods of D 3 LS namely the forward, backward, and the forward-backward methods.

A Wideband Direct Data Domain Genetic Algorithm Beamforming

“…x In [7] it is mentioned that "although the main beam is directed to the signal of interest (SOI) direction and the jammers are nulled correctly but the nulls are not deep enough"; same drawback appears in [1]. Such disadvantage affects the accuracy of SOIs reconstruction.…”

“…Such disadvantage affects the accuracy of SOIs reconstruction. In addition, in [1] and [7], nulls' depths and DOAs estimations' accuracy are found to be frequency dependent. Therefore, selecting one beam pattern corresponding to single sub-band does not assure sufficient nulls' depths to cancel interferers in all other sub-bands.…”

“…That way, the antenna could adaptively minimize the interference power while maintaining the array gain in the direction of the target signal [1][2][3].…”

“…x The problem of frequency dependent estimations of DOAs and nulls' depths [1], [7] could be solved by taking into consideration that in D…”