Enhanced DOA visibility of correlated sources for multistatic shipborne surface wave radar

A modified array interpolation approach to correlated source localization is presented for the surface wave radar (SWR) that employs multiple uniform linear subarrays (ULSAs) mounted on different ships to compose a multistatic shipborne SWR receiving array. This approach that overcomes the main shortcomings of some existing interpolation techniques, comprises three stages: a first stage for preestimating direction-of-arrivals (DOAs) on an assumption that at least a single ULSA is available for correlated source localization, a second stage for specifying a union of nonoverlapping narrow subsectors as the interpolated sector to cover only the preestimates, and a third stage for reestimating DOAs with the virtual uniform linear array (VULA), in which we skip noise prewhitening and appropriately increase the amount of forward/backward spatial smoothing (FBSS) that plays a major role in lowering noise floor while decorrelating correlated sources. Monte Carlo simulations demonstrate the validity of our proposal.