HIGH-RESOLUTION PASSIVE ARRAY-PROCESSING - AN OVERVIEW OF PRINCIPLES

High resolution array processing has been an important field of interest. This is due to the fact that often, and this is particularly true for passive sonar, the array aperture is small, which results in a weak resolving power, and also secondary lobes are difficult to maintain at a sufficiently low-level to reduce the masking effect due to high level jammers. This paper presents an overview of the principles of high resolution passive array processing and of their properties. Performance bouds of array processing are examined, which show that resolving power can be enhanced by increasing the observation time. Resolving power of high resolution methods has the same behaviour, but with a lower gain. High resolution methods beamforming needs an estimate of the number of sources: a unified method is presented which simplifies this problem. Extension to wideband signals is presented and results obtained on real date are shown.