  We focus on developing an effective Direction Of Arrival (DOA) estimation
method for wideband sources based on the gridless sparse concept. Previous
coherent methods have been designed by dividing wideband frequencies into a few
subbands which are transferred to a reference subband using focusing matrices.
In this work, as opposed to the previous techniques, we propose a convex
optimization problem that leads to an accurate wideband DOA estimation method
with no need for any focusing matrix. Moreover, in this method, no initial DOA
estimates are required and it can be used for any arbitrary linear arrays.
Numerical simulations show that in comparison to some well-known techniques,
the proposed method generates outstanding accuracy and better robustness to
noise. The effectiveness of the method is also verified in presence of close
adjacent sources.
