A method of determining relative positions of at least three antennas of an antenna array utilized in an interferometer arrangement, the antenna array arranged to receive a plane wave of electromagnetic radiation from a transmitter located at an unknown angle; each of the antenna being spaced from one another in an x dimension and a y dimension, the x and y dimensions being orthogonal; the method comprising the steps of: a) determining a maximum size allowed for the antenna array in the x dimension and the y dimension; b) determining the number of antennas and number of antenna pairs to be used for receiving the plane wave of electromagnetic radiation and making phase difference measurements; c) selecting a unit spacing for each of the x and y dimensions determined by the frequency of the electromagnetic radiation to be received and the unambiguous angle range desired in each of the x and y dimensions; d) producing a set of physical spacing matrices where K = [ K x K y] and K x and K y are the respective x - and y- coordinate spacings; the integer values of K x and K y representing multiples of the unit spacing for the respective x and y dimensions; and where producing the set of physical spacing matrices includes iterating over all possible physical x- and y- coordinates; e) determining sets { K' x} and { K' y} of meta x-coordinate spacings and meta y -coordinate spacings respectively, such that: highest common factor of the spacings of each K' x is 1; highest common factor of the spacings of each K' y is 1; f) deriving a set of candidate geometries (K,Q x,Q y) by finding combinations of K, K' x and K' y which have respective integer mapping matrixes O x, Q y such that respective integer mapping matrices O x and O y applied to the physical spacings K x and K y satisfy Q x K x = K' x and QxKy =0, and Q y K y = K' y and QyKx = 0; g) for each candidate geometry, analysing candidates of the candidate set to identify a preferred physical arrangement of the plurality of antennas in the antenna array, comprising: (i) finding matrices P x and P y such that P x K' x = ξ and P y K' y = ξ, where ξ is a column vector of all ones (ii) rejecting candidates of the set with no solution; and (iii) recording candidate geometries (K,Q x,Q y,P x,P y) in the candidate set; (iv) for each candidate antenna geometry, statistical measurement accuracy is calculated and (v) select the best candidate antenna geometries for constructing a base plate of the antenna array. a) determining a maximum size allowed for the antenna array in the x dimension and the y dimension; b) determining the number of antennas and number of antenna pairs to be used for receiving the plane wave of electromagnetic radiation and making phase difference measurements; c) selecting a unit spacing for each of the x and y dimensions determined by the frequency of the electromagnetic radiation to be received and the unambiguous angle range desired in each of the x and y dimensions; d) producing a set of physical spacing matrices where K = [ K x K y] and K x and K y are the respective x - and y- coordinate spacings; the integer values of K x and K y representing multiples of the unit spacing for the respective x and y dimensions; and where producing the set of physical spacing matrices includes iterating over all possible physical x- and y- coordinates; e) determining sets { K' x} and { K' y} of meta x-coordinate spacings and meta y -coordinate spacings respectively, such that: highest common factor of the spacings of each K' x is 1; highest common factor of the spacings of each K' y is 1; f) deriving a set of candidate geometries (K,Q x,Q y) by finding combinations of K, K' x and K' y which have respective integer mapping matrixes O x, Q y such that respective integer mapping matrices O x and O y applied to the physical spacings K x and K y satisfy Q x K x = K' x and QxKy =0, and Q y K y = K' y and QyKx = 0; g) for each candidate geometry, analysing candidates of the candidate set to identify a preferred physical arrangement of the plurality of antennas in the antenna array, comprising: (i) finding matrices P x and P y such that P x K' x = ξ and P y K' y = ξ, where ξ is a column vector of all ones (ii) rejecting candidates of the set with no solution; and (iii) recording candidate geometries (K,Q x,Q y,P x,P y) in the candidate set; (iv) for each candidate antenna geometry, statistical measurement accuracy is calculated and (v) select the best candidate antenna geometries for constructing a base plate of the antenna array. (i) finding matrices P x and P y such that P x K' x = ξ and P y K' y = ξ, where ξ is a column vector of all ones (ii) rejecting candidates of the set with no solution; and (iii) recording candidate geometries (K,Q x,Q y,P x,P y) in the candidate set; (iv) for each candidate antenna geometry, statistical measurement accuracy is calculated and (v) select the best candidate antenna geometries for constructing a base plate of the antenna array.