High-Squint FMCW SAR Imaging via Wavenumber Domain Algorithm

Hui Bi,Hao Li,Wei Liang,Wang Zheng

doi:10.1155/2021/5551674

Abstract

Nowadays, because the frequency modulation continuous-wave (FMCW) synthetic aperture radar (SAR) shows good potential in minimal transmission power and weight reduction of radar systems, it has been widely used and has become a common technique in modern short-range high-resolution earth observation. Different from the conventional pulsed mode, the stop-to-go approximation is not valid in FMCW SAR. Thus, the typical SAR imaging methods need to be modified to adapt the continuous-wave scheme in practical data processing. In this letter, a wavenumber domain algorithm (WDA) is derived and used for the FMCW SAR imaging under squint and high-squint cases. With the help of the exact scene recovery ability of the proposed WDA, we can achieve the accurate recovery of the considered scene even when using the collected high-squint data and hence obtain the well-focused high-resolution image of the considered scene. Experimental results with simulated and airborne data verify the effectiveness of the proposed method.

Highlights

Synthetic aperture radar (SAR) is an active microwave imaging system usually mounted on a satellite or airplane to achieve high-resolution earth observation [1,2,3]
Different from the typical pulsed imaging mode, frequency modulation continuous-wave (FMCW) SAR transmits the long sweeps in the data collection process, which will cause the variation of instantaneous slant range and makes the stop-to-go approximation not valid any more [5, 9]
Experimental results show that the proposed method can achieve accurate recovery of the considered scene even when using the collected high-squint data, which means that it can be regarded as a general technique for FMCW SAR imaging in any squint angle

Summary

Introduction

Synthetic aperture radar (SAR) is an active microwave imaging system usually mounted on a satellite or airplane to achieve high-resolution earth observation [1,2,3]. An accurate representation of the WDA algorithm is derived for the FMCW SAR image focusing in squint and high-squint cases. Experimental results show that the proposed method can achieve accurate recovery of the considered scene even when using the collected high-squint data, which means that it can be regarded as a general technique for FMCW SAR imaging in any squint angle.

FMCW SAR Imaging

WDA-Based Squint and High-Squint Imaging

Experiment via Simulated Data

Experiment via Real Data

Conclusion