Hardware Implementation Of Eight-Element Toroidal Array DOA Estimation Algorithm

With the continuous development of modern technology and military,DOA(Direction Of Arrival),which is an important part of array signal processing,has achieved rapid development in recent years.The DOA estimates not only have a wide range of applications in the military field,but also a growing demand for civilian use.How to realize the high precision and high speed of DOA estimation algorithm in hardware becomes a research hotspot.This paper designs and implements a digital hardware platform based on DOA estimation algorithm for eight-element ring array.Two DOA estimation algorithms,MUSIC(Multiple Signal Classification)algorithm and FFT(Fast Fourier Transform)algorithm,are implemented on this platform.The main research contents of this paper are as follows:(1)Design and complete FPGA implementation of MUSIC algorithm for eightelement ring array.The design of the digital hardware platform includes the design of the peripheral circuit of ADC(Analog to Digital Converter),FPGA(Field Programmable Gate Array)Peripheral Circuit Design,Clock chip circuit design and power system design.The design principle and precautions of each module circuit are elaborated in the paper,and the performance test of each module of the digital hardware platform is carried out.(2)The FPGA implementation of the MUSIC algorithm for the eight-element ring array was designed and completed.The method includes preprocessing the signal collected by the ADC,and realizing converting the complex domain to the real number field;Construction of a covariance matrix;Eigenvalue eigenvectors of covariance matrices are obtained by spatial rotation using Jacobi method,Using CORDIC algorithm to obtain the arctangent value in Jacobi algorithm.Using the orthogonality of the array direction vector and the noise feature vector to construct the pseudo-spectral function and search for the outgoing wave direction.Finally output in the future wave direction in the FPGA.The final test shows that the MUSIC algorithm of the eight-element ring array achieves a direction error of 0.3 degrees in the FPGA.The time taken was approximately 93.45 microseconds.(3)The FPGA implementation of the FFT algorithm for the eight-element ring array is designed and completed.The theoretical principle and hardware implementation process are elaborated.After time-consuming analysis of each module of the MUSIC algorithm,the MUSIC algorithm takes the longest time to download the pseudo-spectral function sampling module,reduces the number of sampling points of the pseudo-spectral function,and performs FFT and IFFT on the pseudo-spectral function in the FPGA(Inverse Fast Fourier)Transform),the direction search of the new pseudo-spectral function,and finally output in the future wave direction in the FPGA.The final test shows that the FFT algorithm achieves a direction error of 0.6 degrees in the FPGA,which takes 11.8 microseconds,which is 87% less than the MUSIC algorithm.(4)The testing of each module of the digital hardware platform was completed,and the corresponding test results were given.The MUSIC algorithm and the FFT algorithm are measured in the FPGA,and the test results are given.