Direction Finding Method And FPGA Simulation Implementation Based On Multi-level Virtual Baseline Interferometer

The frequency of the signal in the modern radio field is getting higher and higher,and the bandwidth of the signal increases,too.This gives new challenges to the direction finding system.Modern society requires the system not only for greater bandwidth,higher frequency signal but also for higher accuracy.And at the same time keep the system's small volume,small weight,fast response speed.For the interferometer,in order to match the high frequency electromagnetic wave,the length of the interferometer becomes very short,which proposes a high requirement for the antenna size of the interferometer system.In this paper,the interferometer direction finding system I designed based on the two level virtual baseline can improve the can maximize the improvement of fuzzy correct rate,and at the same time keep the angle accuracy high precision.In this paper,we first introduce the interferometer direction finding system,and compare the phase interferometer and the related interferometer in one-dimensional case,and analyze the advantages and disadvantages of them refer to the simulation results.Because the phase interferometer is simple and easy to implement,ordinary one-dimensional,right-angle matrix use phase interferometer.Then,this paper focuses on the solution of the multi-baseline phase interferometer.Because the accuracy of the phase interferometer is determined by the longest baseline of the antenna array,the design of the multi-antenna array is to improve the correctness of the solution.In this paper,for the solution of the fuzzy probability of multi-baseline phase interferometer,the paper analyzes the situation of the second-level baseline design from the correct solution probation probability of the two-stage virtual baseline.The problem of correct solution of fuzzy probability of two-level virtual baseline interferometer is solved by simulation and theoretical derivation.The relationship between solution probability and antenna position and signal-to-noise ratio is obtained.Through the solution of the fuzzy probability between the two baselines,it extends to the range of the multi-baseline phase interferometer,and the position of the antenna is guaranteed to reach the maximum solution of the ambiguity probability every two stages,thus increasing the solution of the whole multi-baseline interferometer Probability.Last,a set of multi-baseline phase interferometer direction finding system is designed by using the optimal solution fuzzy probability antenna configuration method.The design of the antenna is designed with MATLAB and the L-type two-dimensional phase interferometer system with the same antenna formation is simulated.The accuracy of the direction finding is verified by adding different noise and channel error.Then,the one-dimensional phase interferometer is realized on the FPGA,and the result is compared with the result of MATLAB.Simulation and test results show that the antenna array scheme designed according to the algorithm proposed in this paper can realize the high accuracy and high accuracy of the direction finding in the range of design requirements.