Abstract
According to the problems that the mismatch between the real source location and the dictionary grid leads to the great error of Direction Of Arrival (DOA), an Off-Grid DOA estimation based on modified Iterative Adaptive Approach (IAA) is proposed (OGIAA). Firstly, the signal power spectrum obtained by the IAA is modified, and the corresponding grid angle of the peak power is read out as the coarse estimation results. Then, the square error cost function is expanded to the second order Taylor expansion and minimized to obtain the initial offset. Finally, the power component and offset are optimized alternately to achieve high precision off grid DOA estimation. Theoretical analysis and simulation results show that the implementation process of this method is simple, and it can accurately estimate the source angle of the migration grid without regularization parameters. It also has higher estimation accuracy on non-uniform arrays with more degrees of freedom.