Research On The Direction Of Arrival Estimation Algorithm Of GNSS Matching Spectrum Interference

The widespread application of Global Navigation Satellite System(GNSS) in military has led to intensified navigation warfare. As efficient wideband interference, match spectrum interference has been widely used. By the DOA estimation of the interference, on the one hand it can locate the interference source in order to take relevant measures, it can also form null of gain pattern in the direction of the interference so as to achieve the purpose of suppressing interference.With the continuous development of array signal processing, the high resolution DOA estimation algorithm for the narrowband signal has been mature at present. So, the DOA estimation algorithm for the wideband signal has become a study focus among native and foreign researchers. At present, DOA estimation algorithm of wideband signal has large computation and high complexity. Besides, number of interference can be estimated is limited to the array's degree of freedom. Based on reasons above, this paper aims at the DOA estimation algorithm of GNSS matching spectrum interference.Firstly, this paper proposes the DOA estimation algorithm of single matching spectrum interference. By analyzing the characteristics of GNSS matching spectral interference, square focus method is applied to transfer DOA Estimation of matching wideband spectrum interference to that of single tone. Complexity, validity and the estimation performance of the proposed algorithm are analyzed theoretically and confirmed by simulations. Simulations show that the proposed algorithm realizes the high precision estimation of DOA on the basis of reducing the calculation complexity.Secondly, this paper researches on multi-component signals separation algorithm based on the high-order IIR notch filter. The performance of the high-order notch filter has been studied based on analysis of the performance of the 2-order IIR notch filter by the way of cascade, and proposes the multiple signals separation algorithm based on this filter. This algorithm provides foundation for research on DOA estimation algorithm of multi-component matching spectrum interferences.Finally, this paper studies the DOA estimation of the multi-component matching spectrum interferences based on methods above. It makes the N-component matching spectrum interferences into N-component single tone interferences by square focus. Then suppresses N-1 component single tone interferences using high-order IIR notch filter based on the multi-component signals separation algorithm, and only one single tone interference remains. So far, the problem of DOA estimation of multi-component spectrum interferences turns into that of one single tone interference. Theoretical analysis and simulation results have demonstrated that the proposed algorithm has obvious advantages over the traditional algorithms, such as simpler structure, the less computation and the interference source number that can be estimated doesn't depend on antenna array's degree of freedom. The proposed algorithm provides a new perspective for the DOA estimation of multi-component GNSS matching spectrum interferences.