Improved algorithm for high performance space-time 2-dimensional angle estimation

Jamming angle estimation is the fundamental issue of digital array radar for anti-jamming improvement. A new two-dimensional high-performance angle estimation algorithm based on space-time DOA matrix is proposed in this paper under the circumstance that the element spacing of digital array antenna is larger than half wavelength, which leads to phase ambiguity for large jamming angle. Firstly, the space-time DOA matrix is calculated and the eigenvalue decomposition is carried out. Then, the phase unwrapping of each estimated steering vector is performed respectively, which fully uses the matching characteristic between space-time matrix eigenvector and the wave-oriented vector. Finally, the least square solutions of each wave angle are obtained using a series of equations from the estimated steering vector. The phase ambiguity problem is solved by calculating the correlation between the steering vectors corresponding to the set of fuzzy solutions and the steering vectors obtained from estimation, and then choosing the maximum correlation value as the true solution. The simulation and experimental results of digital array antenna demonstrate that the proposed algorithm present higher angle measurement accuracy and more robust performance than those of the space-time DOA matrix method.