Suppression of sea clutter with orthogonal weighting for target detection in shipborne HFSWR

It is difficult to detect a target submerged in the spread spectrum of the first-order sea clutter in shipborne HFSWR (high frequency surface wave radar). Based on the space-time distribution of the first-order sea clutter, a technique for the detection of a ship in the spread-clutter spectrum is presented, which can completely suppress interference coming from a known incident direction. The influence of orthogonal weighting on the mainbeam directed at the target is slight when interference is outside the mainbeam. Angle measurement can then be accomplished as for an onshore HFSWR. However, suppression of interference coming from within the main target beam would result in this mainbeam splitting into two beams. It is shown that amplitude comparison of the two split beams can be used to determine the azimuth of the target. Processing the results from the experimental data demonstrate reliable ship detection and estimation on the Yellow Sea of China