Study On Array Optimization And Pattern Shaping Technology Of Airborne Phased Array

With the development of array signal processing technology,phased arrays are more and more widely used in radar,satellite communications and other fields,and the optimization of phased array pattern performance has also become the focus of research.There are two main ways to optimize the performance of the phased array pattern:one is to optimize the spatial distribution structure of the array,that is,layout optimization;the other is to optimize the weighting of each array element,that is,pattern shaping.Obtaining the optimal array element distribution under specific constraints and finding the weight vector that satisfies the desired pattern performance of the array are the main research goals of this thesis.The main research contents and work of this thesis are as follows:1.For common-aperture staggered sparse arrays,two optimization methods for common-aperture sparse arrays are studied.One method is to construct a new fitness function by weighted summation of the fitness functions of multiple arrays,and then use the particle swarm algorithm to solve the multi-array simultaneous optimization problem.The other method is based on the characteristics of multi-objective optimization functions,introduces Pareto optimal theory,and develops a non-dominated sorting genetic algorithm with elite strategy(Elitist Non-dominated Sorting Genetic Algorithm,NSGA?).The common aperture array optimization method improves the pattern performance.2.Aiming at the scene with fixed array structure,the pattern forming technology is researched.Based on the adaptive optimal weight vector formula,a pattern forming algorithm based on orthogonal projection theory and an improved beam center offset pattern forming algorithm based on oblique projection theory are introduced.The latter can control multiple points at the same time.level.On this basis,an oblique projection pattern forming algorithm based on the idea of dimensionality reduction is developed,which converts the two-dimensional pattern forming problem into a one-dimensional pattern forming problem and reduces the running time of the algorithm.3.For conformal polarized arrays,two pattern shaping algorithms are studied based on the characteristics of the transmitting signal model and the receiving signal model,respectively.The transmit beamforming of a conformal polarized array is the result of vector combining.Combined with the characteristics of transmit beamforming,the idea based on alternating projection is applied to the pattern shaping of transmit beamforming,so that the transmit beamforming can approximate the desired value on the polarization and pattern;another method is to assign the pattern to the pattern.The shape problem is transformed into an optimization problem that satisfies the convex optimization condition,and the optimization problem is solved by convex optimization.Compared with the conventional array,the receiving beamforming of the conformal polarized array is different from the polarization of each array element,so that the response of the array element to the signal is no longer consistent.Combined with the characteristics of the received signal model,the idea based on alternating projection is still applicable to the pattern shaping of receive beamforming.Compared with the transmit,only the formula for calculating the pattern has changed;in addition,by assigning the receive pattern A convex optimization model is established by solving the shape problem,and a shaping method suitable for receiving beamforming is developed.At the same time,the effectiveness of the algorithm is verified by simulation experiments.