Abstract:

In order to improve the accuracy of direction finding with the conventional L-shaped array, an interferometric-like L-shaped array is proposed, which is based on the interferometry theory and the techniques of direction of arrival (DOA) estimation of conventional L-shaped array. The interferometric-like L-shaped array leads to aperture extension and higher accuracy of DOA estimation. The interferometric-like array with the baselines greater than a halfwavelength results in the grating lobes in the combined array beampattern and ambiguity in DOA estimation. A dualsize estimation of signal parameters via rotational invariance techniques (ESPRIT)  based algorithm is used to resolve the ambiguities, where the short baseline yields unambiguous but highvariance direction cosine estimates to disambiguate low variance but cyclically ambiguous estimates from the longer baseline, then lower variance and nonambiguous estimates are achieved. The lower bound of mean square error of direction cosine is approximately calculated. The relation of the baseline ambiguity threshold and the signal to noise ratio threshold is analyzed. Simulation results demonstrate the effectiveness and high accuracy of this interferometric-like L-shaped array.