Grating lobe suppression in focussed energy delivery for precision electronic warfare

Abstract

Focussed energy delivery (FED), which transmits energy to a specific area by ultrasparse arrays, is the core technique of precision electronic warfare (PREW). However, array sparsity results in severe grating lobes in practice, which greatly increase the risks of an interference system being attacked and unexpected jamming occurring in other devices. Here, two methods are presented which are aimed at suppressing grating lobes when implementing FED in the application of PREW to avoid the problems mentioned. Regarding the first method, a new metric based on the l ∞ -norm is proposed to measure the maximum grating lobe and introduce the metric to the standard FED model. A multiobjective optimisation problem (MOP) is established and solved by the alternating direction penalty method (ADPM) framework. In the second method, the degrees of freedom of the transmitted signals are extended by equipping each platform with a group of linear uniform antennas. The corresponding MOP is established and block coordinate descent is employed to simplify the problem into two subproblems concerning the amplitude and phase components of the transmitted signals. Then, these two subproblems are solved using Taylor expansion and the ADPM framework. Simulation results are provided to demonstrate the advantages of the proposed methods over the stateof-the-art methods.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

A method for jamming waveform design in precision electronic warfare scenarios

“…Experiments show that the designed jamming waveform can concentrate the energy in the airspace and cover the entire working bandwidth of the jamming target in the frequency domain. This overcomes the shortcomings reported in previous studies [7–13] that the instantaneous signal can only focus on spatial energy in PREW.…”

“…� Experiments show that the designed jamming waveform can concentrate the energy in the airspace and cover the entire working bandwidth of the jamming target in the frequency domain. This overcomes the shortcomings reported in previous studies [7][8][9][10][11][12][13] The rest of this paper is organised as follows. Section 2 establishes the basic model of the PREW scenario and describes the method for obtaining the covariance matrix.…”

“…Because the problem has non‐convex characteristics, the idea of SCP is used to transform the problem into a convex problem, iteratively solve the problem, and partially relax the problem to reduce the complexity. Experiments show that the designed jamming waveform can concentrate the energy in the airspace and cover the entire working bandwidth of the jamming target in the frequency domain. This overcomes the shortcomings reported in previous studies [7–13] that the instantaneous signal can only focus on spatial energy in PREW. In the case of transmitting continuous time‐domain signals, new problems will arise in the arrival delay of signals transmitted by different transmitters to different target areas. To the best of our knowledge, this paper discusses the signal bandwidth limitation that errors may cause by combining simulation scenarios, and verifies the effectiveness of wideband interference signals in the presence of errors for the first time. …”

“…In essence, the above problem is to adjust the covariance matrix of the baseband signal according to the phase difference of the carrier signal caused by different delays from each transmitter to the target area to achieve the effect of FED. It should be noted that in previous studies, the existence of delays of the baseband signal was not considered, because either only the covariance matrix of the baseband signal was optimised [7,8] or only one baseband signal sampling time was considered [9][10][11][12][13].…”

“…Based on Chen's work, the method of using an infinite‐norm instead of an l1‐norm as the regular term was proposed, which further improved the grating effect [12]. To extend the freedom of the transmitted signals, an optimisation model by configuring a set of uniform antennas on each transmitter platform, was proposed [13]. However, these studies have not solved the problem, and only fixed‐frequency signals can be used as jamming waveforms.…”