The Research On Direction Of Arrival Estimation Of Wideband Signals Based On Sparse Array

With the rapid development of science and technology,modern signal signal processing is constantly improving and expanding,among them,array-based signal processing technology is widely used,including radar,sonar,medical diagnosis,electronic detection and many other fields.Wideband signal can carry more information because of the wider bandwidth,and thus have better resolution and anti-jamming capability,which is the characteristics that narrowband signal does not have.In this paper,the Direction of Arrival(DOA)estimation algorithm and the wideband array direction finding machine based on DSP are studied.The main contents are as follows:1.The DOA algorithm of wideband array signal based on signal subspace is studied,which mainly includes non-coherent signal subspace(ISM)algorithm and coherent signal subspace(CSM)algorithm.Among them,the ISM algorithm is used to study the classical ISM algorithm,the modified ISM algorithm to solve the coherent source,the energy-weighted ISM algorithm and the frequency-weighted ISM algorithm to improve the estimation performance.The main research contents of CSM algorithm are the construction of focusing matrix,and three common focusing matrices construction methods are introduced.2.The related principles and methods of DOA estimation based on sparse reconstruction are studied.Firstly,the basic principle of sparse reconstruction and the application of DOA estimation in array signal processing are introduced,including the MMV model.Then,two different DOA estimation methods based on sparse reconstruction are introduced: l1-SVD method and l1-SRACV method,and the processing method of receiving signal as Wideband signal is introduced at the same time.Finally,the algorithm is simulated from the perspective of estimation error,algorithm complexity,solution coherence performance and low SNR performance.3.Focusing on how to utilize the wideband signal information to get efficient direction of arrival(DOA)estimation,a weighed wideband DOA estimation method based on normalized Cramer-Rao bound was proposed.Firstly,it estimates the DOA at different frequencies.Then,the final estimated DOA is got by weighing the original estimated values according to the normalized Cramer-Rao bound value at the corresponding frequencies.The proposed algorithm improve the estimation accuracy and resolution of DOA.Simulation results show the show the feasibility of the algorithm.4.Combined with a broadband array direction finding receiver,the engineering technology of wideband direction of arrival estimation method is studied,mainly including the DSP key technology and multi-core processor based on the algorithm module.DSP key technology section introduces the C6678 kernel,the latest Key Stone architecture,C6678 storage structure and the multi-core communication technology.The algorithm module first introduces the overall design of the direction finding machine and two different work modes.Then,the section compares the two different multi-core DSP parallelization methods and points out the characteristics and application scenario.