Efficient methods to compute azimuth and elevation in high resolution DOA estimation

A number of high-resolution methods used to determine the two-dimensional (α_i, β_i) directions of arrival (DOAs) of a number of plane waves, impinging on a sensor array are discussed. The array possesses an arbitrary geometry, but consists of triplets or quadruplets of sensors that are identical. The data from these sensors is first processed for each independent dimension using an ESPRIT-like subspace-based method. The correct (α_i, β_i) pairs are then determined by considering subspace properties that the proposed data would possess in the noise-free case. An algorithm is devised that potentially improves the parameter estimates and yields the correct parameter pairs while avoiding an extensive search over the two separate one-dimensional parameter sets. Resolution is improved by exploiting the spatial dependence of the measurements when sensor quadruplets are used