1. An apparatus for locating one or more buried objects each characterized by an electromagnetic signal emission, the apparatus comprising: a sensor assembly including a plurality K of sensors each having a sensor axis and producing a time-varying sensor signal S k (t), wherein 1≦k≦K; a processor coupled to the sensor assembly for processing a plurality K of the time-varying sensor signals {S k (t)} representing a first electromagnetic signal emission, including a matrix accumulator for producing a data signal representing a K by K covariance matrix A T corresponding to the covariances of the time-varying sensor signals {S k (t)} over a selected time interval, wherein covariance matrix A T is characterized by a plurality K of eigenvalues {λ k } and associated eigenvectors {V k } and calculating means for producing a data signal representing a field vector of the first electromagnetic signal emission at the sensor assembly, wherein the field vector corresponds to the eigenvector V 1 associated with the largest λ 1 of the eigenvalues {λ k }; and a user interface (UI) coupled to the processing circuit for indicating the first electromagnetic signal emission field vector at the sensor assembly.