Underdetermined direction of arrival estimation of wideband signal based on sparse array

To solve the problem of the mismatch of the wideband underdetermined direction of arrival (DOA) estimation under the condition of the On-grid model, this paper extends the narrowband Off-Grid model to wideband and proposes a new DOA estimation algorithm for Off-Grid sources based on group sparsity. The proposed algorithm first obtains the preliminary estimation result under the current predefined discrete grid through the group sparsity wideband DOA estimation algorithm. Then, the Off-Grid optimisation problem is adopted to calculate the Off-Grid deviation vector. It is also assumed that the off-grid deviation vectors of each frequency subband are exactly the same, thereby reducing the number of parameters to be estimated. Therefore, the proposed algorithm can not only maintain similar or even better estimation accuracy but also greatly reduce the computational complexity. Finally, simulation is conducted and the results verify the effectiveness and performance of the proposed method.