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

Figure 5

Summary of DOA estimations using MPM for a four-element ULA with the number of array elements varying from 6 to 20. Three equal-power incoming signals are from the directions of 𝜙₁=40^∘ to 90^∘, 𝜙₂=𝜙₁+1^∘, and 𝜙₃=𝜙₁+2^∘ with an SNR of 5 dB. The step size of Δ𝜙₁=5^∘ is considered. The figures show the average biases of the estimated directions with array aperture (a) 0.75𝜆, (b) 1.00𝜆, (c) 1.25𝜆, and (d) 1.50𝜆.

(a)

(b)

(c)

(d)