Abstract:

Skywave radar is influenced by the broaden first-order sea clutter Bragg peaks when detecting the slow-moving target such as ships. The multiple layers of ionosphere lead to multimode which gives rise to broaden peaks. The traditional one-dimensional receive array does not provide elevation information so that it mixes signals from different layers but two-dimensional array can resolve the problem at root. The relationship of the beam pattern of two-dimensional non-filled array and two-dimensional spatial distribution of sea clutter under the condition of multimode is studied. A scheme of array geometry is presented which is prepared for spatial filtering. The purity of first-order peaks of sea clutter improves after the unwanted mode is filtered out. Simulation result demonstrates that 20 dB gain of clutter suppression can be achieved from the cross array compared with the one-dimensional array.