An Experimental Comparison of Time Delay Weights for Direction of Arrival Estimation

When direction of arrival is estimated using time differences of arrival, the estimation accuracy is determined by the accuracy of time delay estimates. Probability of large errors increases in poor signal conditions and reverberant conditions pose a significant challenge. To overcome the problems, reliability criteria for time delays and weighted least squares direction estimation have been proposed. This work combines these approaches, and compares several weight criteria for single-frame estimation experimentally. Testing is conducted on different types of audio signals in a loudspeaker experiment. As a result, an optimum combination of weights is found, whose performance exceeds earlier proposals and iterated weighting. Furthermore, the optimum weighting is not dependent on the source signal type, and the best weights are the ones that do not require information about the underlying time delay estimator.