Direction of Arrival Estimation of Wide-band Signals with Planar Microphone Arrays

An approach to the estimation of the Direction of Arrival (DOA) of wide-band signals with a planar microphone array is presented. Our algorithm estimates an unambiguous DOA using a single planar array in which the microphones are placed fairly close together and the sound source is expected to be in the far field. The algorithm uses the ambiguous DOA estimates obtained from microphone pairs in the array to determine an unambiguous DOA estimate for the array as a whole. The required pair-wise DOAs may be calculated using Time Delay Estimations (TDEs), which may in turn be calculated using cross-correlation, making the algorithm suitable for wide-band signals. No a priori knowledge of the true Sound Source Location (SSL) is required. Simulations show that the algorithm is robust against noise in the input data. An average ratio of approximately 3:1 exists between the input DOA errors and the output DOA error. Field tests with a moving sound source provided DOA estimates with standard deviations between 20.4 and 15.2 degrees.