A method is provided for constructing a histogram to represent the root-mean-squared phase differences for a signal received at pairs of elements in an array. A pair-wise element phase difference (“PEP”) between a signal received at an angle of arrival θ1 and a signal received at an angle of arrival θ2 are determined. The difference ΔΨ between the differential phase measurements at θ1 and θ2 is computed. The process is repeated for all unique pairs of angles (θ1, θ2) from 0 to 359 degrees and the results are summed over all PEPs to calculate the root mean squared phase difference √{square root over (ΔΨ2(θ1,θ2))} between two different angles of arrival θ1 and θ2. A two-dimensional histogram is created by pairing the measurements √{square root over (ΔΨ2)} and Δθ, where Δθ=θ2−θ1. The histogram can be used to determine whether a particular array is ambiguous to facilitate design of an array that can resolve and/or minimize ambiguities and so provide more accurate information regarding the source of a received signal.