Abstract: The DOA estimation methods based on the analysis of the noise subspace enable high resolution bearing determination of naval objects emitting hydrouacoustic noise. The knowledge of the objects number is the essential parameter for DOA algorithms. Practically, the number of the objects is unknown. In case of high sea ambient noise to object signal ratio the detection with desired probability is significantly hindered. In the event of system based on the console the detection decision belongs to the operator. The visual analysis of the reception beamformer changes conducts to the intruder detection. Whereas in case of the stand- alone systems the decision making process is performed by the detection and tracking algorithm. This article describes such algorithm based on the analysis of the machine states.