ABSTRACT
Compared to conventional SAR, the signal processing and image focusing of Moon-Based SAR (MBSAR) are more challenging due to the complex observation geometry. The extended synthetic aperture time (SAT) results in a curved trajectory, which, combined with round-trip time delay, introduces phase errors to the MBSAR signal and thus invalidates the stop-and-go assumption. This suggests that the platform’s properties render conventional focusing algorithms ineffective in MBSAR. To address the aforementioned issues, this chapter presents two effective methods to compensate for the stop-and-go error as alternatives in place of the cumbersome iterative method. Subsequently, two range models, one based on the Taylor series expansion, and another developed from the hyperbolic range equation (HRE), are proposed to characterize the phase history of MBSAR. Afterward, the 2-dimensional (2-D) signal spectrum for the non-stop-and-go echo in the context of a curved trajectory is derived, which then serves as the basis for developing the focusing algorithm (in the frequency domain) specifically designed for the MBSAR. Finally, examples of target response simulations are presented to illustrate MBSAR imaging performance.
