Direction-of-Arrival Estimation of Closely Spaced Emitters Using Compact Arrays

Figure 4

Summary of DOA estimations using MPM for a four-element ULA with the number of array elements varying from 4 to 20. Two equal-power incoming signals are from the directions of 𝜙₁=10^∘ to 90^∘ and 𝜙₂=𝜙₁+1^∘ with an SNR of 5 dB. The step size of Δ𝜙₁=5^∘ is considered. The figures show the average biases of the estimated direction. The apertures of the arrays are (a) 0.25𝜆, (b) 0.5𝜆, (c) 0.75𝜆, and (d) 1𝜆.

(a)

(b)

(c)

(d)