Patent ID: 8648749

Claim:
A method of estimating multiple angles of arrival of a target signal received by an array of commutated antenna elements, comprising the steps of: (a) obtaining samples of the received signal from the array of commutated antenna elements and from an element in an array of reference antenna elements; (b) with a computer, processing the obtained samples of the received signal to estimate multiple angles of arrival of a target signal received by the array of commutated antenna elements; and (c) mapping a display over time and frequency of said estimations, with the angle of arrival for a particular sample being represented by a variable color; wherein step (b) comprises the step of: (d) making maximum-likelihood-estimations φ MLE of the multiple angles of arrival at which the target signal is received by the array of commutated antenna elements in accordance with the following computer processing step: ϕ _ 0 ← argmax ϕ ⁢ Color _ * A ⁡ ( A * diag ⁡ ( Energy _ ) ⁢ A ) - 1 ⁢ A * Color _ A n ← a _ k n ⁡ ( ϕ _ ) Color _ n ← ∑ k ∈ R n ⁢ y C , k ⁢ y R , k _ Energy _ n ← ∑ k ∈ R n ⁢ y R , k ⁢ y R , k _ wherein φ 0 approaches φ MLE , the subscript i denotes the iteration number, y C denotes an individual sample of the received target signal obtained from a single commutated antenna array element, y R denotes a sample of the received target signal obtained from the reference antenna array element; n ranges over time and frequency, the vector a k n ( φ ) is the nth row of the matrix A, Color is a vector with tuples that are the color sequence of the target, the tuple Color n denotes the n th color in the color sequence measured using the n th commutated element, R n denotes the set of all k for which the n th commutated element was used, the vector Energy is similarly defined and measures the energy sequence of the target, the n th row and the i th of column of the matrix A is the response of the n th element of the commutated array to a signal from angle φ , with the n th row being given by a k n ( φ ) for some k n , diag(Energy) denotes a diagonal matrix where the diagonal elements are given by the vector Energy and the other elements are zero.