Research On DOA Estimation Algorithms For Narrowband Signal

DOA (Direction of Arrival) estimation is a technology used to determine the signal direction. Its basic idea is to estimate the signal incident angle relative to the array by using the received information of sensor array which are arranged in a certain way in the space. DOA estimation is a fundamental problem in array signal processing, and it has a wide range of applications, such as wireless communication, sound localization, wireless sensor networks, seismology fields and so on.The narrow-band signal DOA estimation is mainly discussed in the thesis. Source can be divided into far-field source and near-field source in accordance with the distance to the array. Narrow-band signal DOA estimation algorithm were studied under the cases of far-field、near-field and both fields.Firstly, CSA-Bartlett algorithm was proposed in the background of far-field source. In the algorithm, the received data by array element was pre-processed through the use of compressive sampling array, then DOA estimation was performed by utilizing Bartlett algorithm. The amount of computation and hardware complexity were reduced, furthermore, estimation accuracy and resolution didn’t experience the degradation significantly although the data was compressed.Secondly, a new algorithm for jointly estimating the frequency, two-dimensional direction of arrival and range of near field sources is proposed in the background of far-field source. The proposed approach requires only four cumulant matrixes and two eigenvalue decomposition to estimate the four parameters and does not require searching for spectral peak or pairing among parameters. The proposed algorithm can be applied in arbitrary Gaussian noise environment since it is based on the fourth-order cumulants. In addition, using Non-symmetrical cross array structure in the thesis, the aperture loss is reduced. The performance of the proposed method is evaluated by some numerical simulation.Finally,a new algorithm for jointly estimating multi-parameters (the frequency, Direction of Arrival and range) of sources is proposed. The proposed algorithm does not require spectral peak search, and can be applied to arbitrary Gaussian noise environment. It can reduce the aperture loss. Moreover, the fourth order cumulant matrices are constructed using the special sensor outputs, and the rank reduction of matrices can be avoided when the far-field sources impinging on an array of sensors. So the proposed algorithm can be used to estimate the parameters of near-field, far-field and mixed sources. The performance of the proposed method is validated by simulations.