A Study on the Feasibility of Stop-and-Go Approximation in FMCW SAR

Abstract

Synthetic aperture radar (SAR) specializes in capturing two-dimensional images of Earth’s surface. Because satellites or aircraft have mainly been used as SAR platforms, pulse radar systems with high peak transmitted power have been preferred for long-range detection. However, because systems based on pulse radar are generally too heavy and expensive, lightweight and low-cost frequency-modulated continuous-wave (FMCW) radar systems have attracted increasing interest, and many studies on FMCW SAR signal processing are being conducted. The pulse duration of FMCW radar is considerably longer than that of pulse radar. Therefore, it is necessary to determine whether stop-and-go approximation (SAG) is still valid for FMCW radar. If SAG is not applicable, an additional, time-consuming range cell migration correction process is required. In this study, the conditions under which SAG can be applied to FMCW SAR were analyzed. Moreover, Ku-band FMCW SAR field tests were conducted to experimentally validate the feasibility of SAG. Several quantitative parameter values demonstrating the advantages of applying SAG were identified.