Research On Fast-algorithm Of Spatial Spectrum And Its Realization

With the development of communication technology of low interception and detection probability, and the electromagnetic environment becoming much worse, it is often needed to process multiple signals in a wide bandwidth at one time, which brings about stricter demand for the real-time property and validity of DOA estimation algorithms. This paper focuses on fast DOA estimation algorithms and their realization in order to reduce the computational complexity by improving these algorithms and realize these algorithms on the FPGA plus DSP platform. The main contents can be summarized as follow:1,Fast DOA estimation algorithms in ULA are studied. A fast algorithm without eigendecomposition and spectrum peak search is proposed based on propagator method. The algorithm can reduce the computational complexity largely. But this algorithm has bad performance in the condition of low SNR. So, a new fast Root-MUSIC algorithm is presented,which can obtain the signal subspace from the covariance matrix without eigendecompsition and spectrum peak search,and has better performance in the condition of the low SNR as well. These algorithms introduced in this paper do not only reduce the computational complexity, but they also improve the efficiency largely with their performance becoming worse to a certain extent.2,Fast DOA estimation algorithms in UCA are studied. The real beamspace-MUSIC algorithm based on the phase mode excitation can reduce the computational complexity when the number of array element is large. But it needs 2-D spectrum peak search. With an eye to this, a UCA-ESPRIT algorithm without 2-D spectrum search is introduced. However, the performance of this algorithm is limited by the aperture of the array and the number of sensors. So, a fast algorithm for 2-D direction-of-arrival (DOA) estimation is given on the basis of FD Root-MUSIC algorithm. This algorithm utilizes the method of finding the roots of multinomial instead of spectrum peak search. As a result, it has a lower computational complexity in comparison with the MUSIC algorithm and it is free of the aperture of the array and the number of sensors limitation. Meanwhile, in order to reduce the computational complexity farther the algorithm applies the linear search method instead of finding the multinomial roots.3,Fast realization of the linear search algorithm is studied. Firstly, the problem of quantification errors and calculation errors is analyzed before the algorithm is realized on hardware platform, and the flow of fixed-point simulation is introduced. Then, based on the result of fixed-point simulation in MATLAB, the realization structure of fixed-point data in FPGA is designed. Finally, a preliminary assessment of the amount of necessary hardware resources together with the performance of this algorithm is presented.4,Program of the linear search algorithm in FPGA plus DSP platform is studied. Firstly, every part of the process platform is introduced. Secondly, assignment allocation on this platform is fixed according to characteristics of hardware and algorithm, and the detailed realization flow chart is given. Then, the algorithm is carried out by programming and simulation in FPGA plus DSP platform, including: calculation of covariance matrix, eigendecomposition, judging the number of signals, finding the coefficients of polynomial and roots of the polynomial. And simulation results verify the design. Finally, resources utilization and performance for the spatial spectrum direction-finding algorithm are evaluated on the present platform.