Research On Irregular High Frequency Array Synthesis And DOA Algorithm

High frequency surface wave radar has been paid more and more attention because of its over-the-horizon detection,all-weather work and strong anti-interference ability.It is widely used in military and economic fields such as long-range early warning,Monitoring and so on.However,due to the high frequency radar itself operating frequency(3 ~ 30MHz)re strictions,the receiving array antenna size is large.The array in the island or on the ship array can not get enough layout space to be arranged into uniform linear array or flat array.Aiming at this problem,this paper studies the array synthesis and DOA estimation of irregular high frequency arrays.Firstly,the mathematical model of the irregular high frequency array is studied.The so-called irregular array is relative to the uniform linear array.In this paper,the arc array and the irregular linear array are the main research objects,and the expression of the two arrays is given.The performance of the array is analyzed.On the basis of this,two basic DOA estimation algorithms(Capon algorithm and MUSIC algorithm)are applied to these two arrays,and compared with the algorithm applied to the uniform linear array of the same aperture,the performance of the basic DOA estimation algorithm is analyzed.Then,when the azimuths of the circular array and the irregular arra y are compared with the uniform linear array of the same aperture,the sidelobe level of the two arrays is higher than that of the uniform linear array,and the beam direction of the irregular linear array occurs Offset,resulting in the problem of distortion of the pattern,the array pattern synthesis.Because the array structure is no longer uniform linear array,the traditional analytic method is no longer applicable,consider the optimization algorithm applied to the irregular high frequency array pattern synthesis problem,and mainly research on genetic algorithm and particle swarm algorithm.The two optimization algorithms are applied for optimization of only optimized for element amplitude,optimization of only the element phase and the optimization for both at the same time.Only the method of array element amplitude optimization is used to synthesize the circular array and the irregular straight line pattern.Combining the advantages of genetic algorithm and particle swarm optimization algorithm,an array pattern optimization method based on hybrid genetic particle swarm optimization is proposed and applied to circular array and irregular array to verify the effectiveness of the algorithm.Next,we study the DOA estimation algorithm of coherent and no n-coherent sources for two arrays.For the non-coherent signal source,the MUSIC algorithm based on second derivative,the improved MUSIC(MMUSIC)algorithm and the improved conjugate MUSIC(MCMUSIC)Algorithm are studied and have simulation analysis for algorithm performance.For the coherent signal source,the virtual interpolation technique is used to realize the DOA estimation of the irregular high frequency array and the effectiveness of the simulation algorithm.