An array processing algorithm based on artificial neural networks (ANNs) is proposed to estimate the directions of arrival (DOAs) of moving humans using a small sensor array. In the approach, software beamforming is first performed on the received signals from the sensor elements to form a number of overlapping beams. The received signals from all the beams produce a unique "signature" in accordance with the target locations as well as the number of targets. The target tracking procedure is handled by two separate ANNs in sequence. The first ANN determines the number of targets, and the second ANN estimates their respective DOAs. The ANNs are trained using simulation data generated based on a point scatterer model in free space. The proposed approach is tested using measurement data from two loudspeakers and two walking humans in line-of-sight and through-wall environments.
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