Analysis of frequency number and frequency offset on STAP for sapceborne sparse array GMTI radar with multiple carrier frequencies

Ground moving target indication (GMTI) is an important, challenging application of spaceborne sparse array radar. Due to the long baseline of the sparse array, the main beam clutter Doppler spread will become narrower, which can improve the capability of slow ground moving target indication. However, the undersampling of sparse array will bring grating lobes and high sidelobes in the synthesized pattern, which will cause the blind-zone and angle-ambiguity problems of detection. These problems can be mitigated by using multi-carrier-frequency technique. Based on the Minimum Redundancy Linear Arrays (MRLA), the paper presented preliminary simulations on space time adaptive processing (STAP) with different carrier-frequency offset and different carrier-frequency number. Simulations showed that the design between the carrier-frequency offset and the carrier-frequency number should be a compromise between detection performance and computation complexity with the same element number and the same array configuration.