Clutter Characteristic Analysis and Grating Lobe Suppression for Distributed Small Satellite Space-Based Early Warning Radar

The distributed small satellite space-based early warning radar (SBEWR) can increase the azimuth-dimensional aperture size by using multiple smaller antennas. This article proposed the combination of real and virtual apertures (CRVA) approach to reduce the effect of grating lobes. It complements the space-time echo signal at the baseline by trading time for space. There are two problems caused by CRVA. One is the new constraints on parameters, and the other is the modulation phase due to the Earth's rotation. In terms of these problems, pulse repetition frequency, array size, and pulse number of the distributed small satellite SBEWR are analyzed. A set of simulation parameters is designed to verify the effectiveness of the approach. Aiming at the modulation phase caused by Earth's rotation, the modified echo is used to match the search space-time steering vector to the target space-time steering vector for space-time adaptive processing. The simulation results show that CRVA can effectively equate the space-time echoes of the sparse array to that of the ideal uniform linear array.