Simultaneous estimation of source number and directions-of-arrival via blind beamforming

Blind beamforming algorithms have the ability to recover the desired signals from sensor array outputs without any prior knowledge of the direction-of-arrivals (DOAs). Non-Gaussian signals with negative kurtosis can be automatically captured by the multistage constant modulus (CM) array, which is the most striking blind beamforming algorithm and has been widely discussed in literatures. However, the sources number must be pre-determined in all kinds of blind beamforming algorithms. Based on the multistage CM array, we present a new method in this paper. It is designed to recover the desired signals and automatically determine the number of sources simultaneously. If the array geometry is known, the DOAs of all sources also can be estimated at the same time. The performance of the new method was analyzed via computer simulations and water tank experiments, and compared with that of other DOA estimation algorithms including "non-blind" and "blind" ones under the assumption of knowing the sources number. The new method shows better results in all considered situations.