  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.
