Research Of DOA Estimation Algorithms Based On Priori Knowledge Of Signals

With the development of communication technology, the DOA estimationtechnology has achieved great progress as an important branch of array signalprocessing. Traditional DOA estimation technique can estimate the direction ofarriving signals in the case that the signals are completely unknown for the receiver.In recent years, DOA estimation technology is not only confined to the militaryfileds, such as the navigation and positioning, the electronic surveilance and combat,etc. but also applied to many civilian fileds, such as mechanical and electricalmeasurements, biomedicine, etc. In these applications, the priori knowledge of thesignals is usually completely known for the receiver. This has promoted the researchof DOA estimation algorithm based on priori knowledge of signals.The paper makes discussions and researches to DOA estimation algorithmsbased on priori knowledge of signals. The paper mainly analyzes two types ofalgorithm. One type is the maximum likelihood estimation algorithms based on themaximum likelihood criterion, such as DEML algorithm, CDEML algorithm,WDEML algorithm, etc. The maximum likelihood estimation algorithm has a veryhigh accuracy and resolution. Compared to the traditional DOA estimation algorithm,it has made great improvement in performance, but it has the problem that thecomputation is large. The other make DOA estimation through the iterativetechnology by using the priori knowledge of signals, such as MSWF-MUSICalgorithm, PASI algorithm in linear array, etc. Compared to the traditional DOAestimation algorithms, the algorithms using the iterative technology usually hasoutstanding performance, for example it can adapt to low SNR and low snapshops, itcan improve the accuracy and reduce the computational complexity, etc.For maximum likelihood estimation algorithms, this paper mainly analyzesvarious factors which influence the performance of algorithms and makes acomparison to the MUSIC algorithm, then sums to obtain the advantages anddisadvantages of the algorithm. We also analyzes the influence of changes ofsignals’ priori knowledge used by receiver on this algorithm and gets thecorresponding conclusions and laws. For the DOA estimation algorithm usingiterative technique, the paper mainly studies some of the characterstics that it hasand analyzes the advantages of algorithms’ performance and computationalcomplexity which iterative technique brings.For the limitations problem of the application of the PASI algorithm in thelinear array, this paper proposes a PASI algorithm based on array translation in thecircular array, which solves the problem that the PASI algorithm can’t be used in other forms of array because of the difficulty to construct appropriate subarray. Thisalgorithm constructs subarrays by using the way of array translation and receivessignals through these subarrays. Then the signals receiving through this way can beused in PASI algorithm to estimate the direction of signals. We make the simulationanalysis of performance for the proposed algorithm and make comparisons withother DOA estimation algorithms based on the priori knowledge of signals.