SAR Focusing of Mobile Apres Surveys

The Autonomous Phase-Sensitive Radio Echo Sounder (ApRES) is a relatively inexpensive ice-penetrating Frequency-Modulated Continuous-Wave (FMCW) radar that is widely utilized in the glaciological community to obtain estimates of ice-sheet basal melt, vertical strain, and compaction rates [1]. However, these instruments are designed for stationary deployments, which prevents glacier- and catchment-scale surveys [2]. To expand the range of available applications, we assess the feasibility of mobile ApRES surveys. Our in-vestigation reveals that utilizing the ApRES in this manner introduces artifacts into the raw data. This paper character-izes the two types of artifacts (Doppler Blurring and grating lobes), investigates the conditions for when they occur, and attempts to correct them by modifying synthetic aperture radar (SAR) focusing algorithms for FMCW radars. We ul-timately identify the main obstacle in focusing radargrams from mobile ApRES surveys to be grating lobes; future work that reduces the presence of this artifact could enable more widespread use of mobile ApRES surveys.