Array DOA Estimation And Error Calibration

DOA(Direction of arrival)estimation is an important research area of array signal processing,widely used in many fields,such as electronicwarfare,radar,biomedicine,etc.However,in actual use,it is inevitable that there will be various errors.The existing errors will seriously deteriorate the direction finding performance and system output performance,and there are also different correction algorithms for different array forms.Therefore,it is of great significance to study the correction algorithms of various arrays,suppress the influence of errors on direction finding,and improve the performance of direction finding.The thesis deeply researches various existing error correction algorithms,analyzes the advantages and disadvantages of the existing correction algorithms,and combines the existing correction algorithms to propose a calibration method suitable for any array.This method is based on strict electromagnetic Analyze and compare this method with the method of establishing the relationship between the pattern in the array and the isolated pattern using least squares.The paper introduces the mathematical principles applicable to arbitrary array correction algorithms through detailed theoretical derivation.The electromagnetic simulation software FEKO was used for the linear array and the conformal array as simulation examples to verify that the new method has good effects on different forms of arrays.At the same time,it is compared with the pattern reconstruction method in electromagnetic software simulation.Simulation results show that the new method has a good correction effect on various forms of arrays,and has more advantages than the pattern correction method,and has more accurate estimation performance in DOA estimation.At the same time,the new method is also more widely used and more applicable.Finally,since the actual incoming wave estimation is always done on the baseband,in the work of this paper,we will use the data sampled by the multi-channel ADC at the intermediate frequency to construct the true steering vector,and use it directly in Incoming wave estimation.The advantage of this method is that all errors of the entire array can be corrected at the same time,including amplitude and phase errors,mutual coupling errors,and so on.Therefore,in order to verify the effectiveness of the method in engineering applications.This article designs a set of adaptive antenna direction finding verification system platform.The antenna forms are quaternary linear array and quaternary conformal array,four RF channels,and a high-performance digital signal processing board.Guide vector to search for spectral peaks.At the same time,the active unit pattern is measured,and the direction of the incoming wave is measured using the active unit pattern.The results show that the new method has higher direction finding results and higher output spatial spectrum.It is verified that the new method has better correction effect than the active cell pattern method in actual engineering applications.