Beamspace approach for detection of the number of coherent sources

A beamspace approach is presented to detect the multiplicity of impinging sources on the sensor array for the direction of arrival estimation problem. The method applies to the coherent signals and can also be used to detect the presence of interfering multipath signal. In many applications, the signal to noise ratio is not sufficient to resolve multiple sources with close spatial frequencies. The suggested method is to detect the presence of an interfering secondary source which can not be possibly resolved.