“…The array measurements are modeled as where s(t) = [s 1 (t), · · · , s d (t)] T is the signal vector, n(t) = [n 1 (t), · · · , n M (t)] T contains the additive sensor noise, and A = [a(θ 1 , φ 1 ), · · · , a(θ d , φ d )] is the steering matrix, which consists of d array steering vectors a(θ i , φ i ), i = 1, · · · , d, with θ i and φ i representing the elevation and azimuth angles of the ith signal. Here, d is known to the receiver or estimated by an information theoretic criterion, such as the Akaike information criterion (AIC) [20], minimum description length (MDL) [21], or their computationally efficient variants [22,23]. The array steering vector is given as…”