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.

I. Introduction

Spaceborne synthetic aperture radar (SAR)-ground moving target indication (GMTI) systems have been proven to be of great value in space-to-ground surveillance and reconnaissance, which includes land and maritime traffic monitoring and military surveillance [1]. As a new generation spaceborne SAR, medium-earth-orbit (MEO) SAR has the advantages of large coverage, short revisit time, and long synthetic aperture time. Therefore, MEO SAR-GMTI systems will be very attractive for space-to-ground surveillance and reconnaissance [2].