Improved processing of the casie SAR data

Abstract

In the summer 2009 NASA Characterization of Arctic Sea Ice Experiment (CASIE09), the microASAR, a small LFM-CW SAR, was operated on the NASA Sierra unmanned aerial system (UAS). An overview of the microASAR and its role in CASIE09 are described in [1,2]. While the limitations in the motion measurements stored with the microASAR data during the CASIE09 mission originally precluded full motion compensation, motion data collected for other CASIE sensors can be employed to improve the SAR image focus and calibration. This paper describes the methodology developed to time-align this motion data and applies this data along with other algorithm improvements to the processing of the microASAR data. This paper also presents a concise description of the backprojection image processing used.

Doppler Factor in the Omega-k Algorithm for Pulsed and Continuous Wave Synthetic Aperture Radar Raw Data Processing

“…Real LFM-CW SAR raw data obtained by the micro advanced synthetic aperture radar (MicroASAR) with linear frequency modulated continuous wave (LFM-CW) on board an unmanned aerial vehicle are obtained from "microASAR [28] data courtesy of David G. Long at Brigham Young University [29]". On the other hand, Figure 21 shows a comparison of SAR images obtained between the range-Doppler algorithm and Omega-k algorithm.…”

“…Then, we replace n in Equation (27), finally obtaining a phase in the two-dimensional frequency domain and, consequently, the raw signal in the two-dimensional domain, which is shown in Equation (29).…”

“…The SAR raw data in the two-dimensional frequency domain are shown in Equation (29); therefore, we implemented general focus, which consists of multiplying the data by the reference function is shown in Equation (39).…”