Table 1 IAA algorithm

Repeat:

(a) Calculate the correlation matrix by ${\widehat{\mathbf{R}}}^{\left(i\right)}=\mathbf{A}{\widehat{\mathbf{P}}}^{\left(i\right)}{\mathbf{A}}^H$.

(b) Estimate the spatial components by${\widehat{p}}_k^{\left(i\right)}={\left|\frac{{\mathbf{a}}^H\left({\theta }_k\right)\cdot {\left({\widehat{\mathbf{R}}}^{\left(i\right)}\right)}^{-1}\cdot \mathbf{y}}{{\mathbf{a}}^H\left({\theta }_k\right)\cdot {\left({\widehat{\mathbf{R}}}^{\left(i\right)}\right)}^{-1}\cdot \mathbf{a}\left({\theta }_k\right)}\right|}^2$, for k = 1, 2, ..., K.

(c) If the norm of the difference between ${\widehat{\mathbf{P}}}^{\left(i-1\right)}$ and ${\widehat{\mathbf{P}}}^{\left(i\right)}$ is smaller than a threshold, i.e., ${\delta }^{\left(i\right)}\triangleq \sqrt{\sum _{k=1}^K{\left[{\widehat{p}}_k^{\left(i-1\right)}-{\widehat{p}}_k^{\left(i\right)}\right]}^2}<\epsilon$, the iteration is stopped; otherwise let i = i+1 and go to a).