Research On Key Technologies Of Conformal Frequency Diverse Array

Frequency diverse array(FDA)has become a hot issue in recent years because of its range-angle- time dependent beampattern characteristics.Compared with linear and planar arrays,conformal array has the advantages of easy attachment to the surface of the carrier and the reduction of the aerodynamic effects on the carrier.It is feasible to explore the performance of the combination,but there is little research on the conformal FDA.Utilizing the advantages of conformal array and FDA,this paper first establishes the mathematical model of conformal FDA,and explores the characteristics of the array and researches the related algorithms.Specifically,the main work and innovation points of this paper are as follows:(1)A general model of conformal FDA is established.Based on the existing FDA,the position of array elements is placed in three-dimensional space,and the general common model of conformal FDA is established by modeling the beampattern for each element.The Euler rotation method is used to model the pattern of the array.The transformation frame of the local coordinates and the global coordinates is set up for different elements.Meanwhile,the beampattern characteristics of cylindrical,conical and spherical arrays are analyzed.(2)The log frequency offset beamforming method based on conformal FDA is pre-sented,and the dwell time analysis algorithm of FDA beampattern is proposed and applied to planar frequency diverse array.For conformal frequency diverse array,log frequency offset beamforming is used to achieve the desired unimodal beampattern and eliminate the periodicity of range dimension.For the pulse planar FDA,the quantitative analysis of beam dwell time of given observation point is realized for the first time.The influ-ence of array geometry,time,range,angle and other factors on dwell time is explored by different coding methods of transmitting signal frequency offset,and the beam focusing characteristics is studied.(3)A reduced-dimension-multiple signal classification(RD-MUSIC)parameter es-timation algorithm based on conformal frequency diverse array-multiple-input multiple-output(FDA-MIMO)is proposed.Conformal array is introduced into FDA-MIMO array configuration,and the mathematical model of conformal FDA-MIMO radar is established for the first time.The multiple signal classification(MUSIC)algorithm is used for pa-rameter estimation.Meanwhile,in order to reduce the computation of traditional MUSIC algorithm due to three-dimensional parameter search,a novel reduced-dimension-MUSIC algorithm is proposed.The complexity analysis of RD-MUSIC algorithm is carried out,and the cramér-Rao lower bound(CRLB)based on the parameter estimation of confor-mal FDA-MIMO radar is derived.Numerical simulation shows the effectiveness of RD-MUSIC algorithm.