An Improved Adaptive Received Beamforming for Nested Frequency Offset and Nested Array FDA-MIMO Radar.

Sibei Cheng,Qingjun Zhang,Xinhong Hao,Mingming Bian

doi:10.3390/s18020520

Sibei Cheng, Qingjun Zhang + Show 2 more

Open Access

https://doi.org/10.3390/s18020520

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Abstract

For the conventional FDA-MIMO (frequency diversity array multiple-input-multiple-output) Radar with uniform frequency offset and uniform linear array, the DOFs (degrees of freedom) of the adaptive beamformer are limited by the number of elements. A better performance—for example, a better suppression for strong interferences and a more desirable trade-off between the main lobe and side lobe—can be achieved with a greater number of DOFs. In order to obtain larger DOFs, this paper researches the signal model of the FDA-MIMO Radar with nested frequency offset and nested array, then proposes an improved adaptive beamforming method that uses the augmented matrix instead of the covariance matrix to calculate the optimum weight vectors and can be used to improve the output performances of FDA-MIMO Radar with the same element number or reduce the element number while maintain the approximate output performances such as the received beampattern, the main lobe width, side lobe depths and the output SINR (signal-to-interference-noise ratio). The effectiveness of the proposed scheme is verified by simulations.

Highlights

IntroductionAs a new kind of MIMO Radar, the FDA-MIMO Radar has drawn much attention, and has been widely investigated since the introduction of the concept of the “frequency diversity array”
As a new kind of MIMO Radar, the FDA-MIMO Radar has drawn much attention, and has been widely investigated since the introduction of the concept of the “frequency diversity array”.In contrast to the traditional MIMO Radar, the FDA-MIMO Radar consists of a beampattern that expands from the angle domain to the joint angle-range domain by utilizing a small frequency offset across the array [1]
The FDA-MIMO Radar has continued toplace a lot of emphasis on the exploitation of the benefits that are exclusive to the joint angle-range domain

Summary

Introduction

As a new kind of MIMO Radar, the FDA-MIMO Radar has drawn much attention, and has been widely investigated since the introduction of the concept of the “frequency diversity array”. Radar research is related to optimizing nonuniform frequency offset to obtain modified range-angle beampattern or better output performance [11,12,13,14,15]. FDA-MIMO Radar research is related to optimizing nonuniform frequency offset to obtain modified range-angle beampattern or better output performance [11,12,13,14,15]. A cognitive FDA-MIMO Radar with situational awareness is researched to offset allows single SINR maxima each beam, ensuring the signal information at the receiver maximize theaoutput by for iteratively optimizing thethat frequency offset in a closed-loop control is of better quality. Offset, namedan NNFDA-MIMO Radar, transmits signals and receives the echo signals using the same two-level

Signal

N1 1 d

Through

Conclusions