Research On Key Technology Of Sparse Array Radar Based On Motion Platform

Compared with uniform array,the sparse array can obtain larger array aperture with the same array elements,so it can obtain higher direction-finding accuracy.The array elements are randomly placed and the space between two array elements is no longer limited to half wavelength,so the coupling effect is greatly reduced.Based on these advantages,the sparse array radar has been widely used.Each node can work independently and also can work together in flexible sparse array radar,so it can get higher detection degrees of freedom and better performance,small satellite formation radar is a typical application of this system.This paper mainly research on array optimization,the echo signal compression and transmission between nodes,array error estimation and calibration of flexible sparse array radar.The main work is as follows:How to improve the efficiency of array optimized algorithm for sparse array based on motion platform is studied.The higher similarity between individuals in the initial population results in poor population diversity in genetic algorithm.The genetic algorithm is prone to local convergence in the middle and later iterations.To ameliorate these problems,a new adaptive genetic algorithm is presented.In this algorithm,the optimization speed is accelerated through regulating the operation sequence and the crossover and mutation rate.At the same time,the algorithm can avoid the local convergence.The experimental results show that the proposed algorithm can obviously improve the convergence speed and the convergence probability.For the flexible sparse array radar working in MIMO mode,echo signal transmission between different nodes is required.By analyzing the main parameters of the flexible sparse array radar and the transmission index of the nodes,a method of echo signal compression and transmission based on compressive sensing is proposed.Because the superposition of multiple narrowband linear frequency modulation signals with different carrier frequencies is sparse in fractional Fourier transform domain(FRFT),we can realize the echo signal compression and transmission between two nodes using this feature.Through the simulation experiment,the compression,transmission and recovery of the echo signal can be accomplished better when compression ratio is10 :1.There are channel amplitude-phase errors between the nodes in the flexible sparse array radar,besides each node has its own position errors,which can lead to the decrease of radar detection performance.For the flexible sparse array radar,the basic conditions of the array calibration have been changed because of the movement of the nodes and the change of the application background.In combination with UWB wireless position technology,this paper proposes a scheme for flexible sparse array errors estimation and calibration.The feasibility of the scheme is verified through technical index analysis and simulation test.