Study on the range equation modeling of MEO SAR-GMTI systems

Due to the advantages of large coverage, short revisit time, and long synthetic aperture time, medium-earth-orbit (MEO) synthetic aperture radar (SAR)-ground moving target indication (GMTI) system is an attractive tool for space-to-ground surveillance and reconnaissance. However, the nonlinear motion of MEO SAR and the significant earth rotation dramatically complicate the relative motion between the radar and a ground moving target. Thus, the signal modeling and the design of GMTI methods for MEO SAR are challenging. To provide a basis for addressing this problem, this paper studies the issue of ground moving target range equation modeling for MEO SAR-GMTI systems. In this paper, the range equation of a ground moving target is developed, and the second-order Taylor approximation of the target's range equation is derived. Moreover, numerical simulations are conducted to investigate the accuracy of the derived range equation.