Improvements to MIMO Radio Echo Sounder Array Design for Subsurface Imaging
Abstract
Phased array radio echo sounders offer a way to monitor subglacial features in three dimensions. Such a system would make it possible to monitor englacial storage of surface meltwater, provide a more accurate estimation of ice sheet mass balance, and make it more economical to explore the basal terraces observed at Pine Island Glacier in West Antarctica and the Petermann Glacier in Greenland. However, to date, existing array-based imaging studies have suffered from processing artifacts that make interpretation of bed geometry challenging or impossible. To address this challenge, we analyze and present potential modifications to MIMO system, array, and processing designs. The current system is an 8x8 antenna array which produces images with curved internal and basal layers where off-nadir angles contain information dominated by the nadir reflection. Several potential causes are being investigated including large side lobes, grating lobes, and processing corrections. The side lobes can be reduced and the array factor improved by increasing the number of antennas, which is accomplished by adding external power splitters, switches, and power amplifiers to accommodate more antennas. Grating lobes are eliminated by decreasing the interelement spacing to half-wavelength and changing the antenna design to accommodate the spacing restriction. Lastly, the beamforming code is revised to account for the high bandwidth. Each of these modifications have the potential to significantly improve the 2D and 3D imaging capability of MIMO radar sounding of subglacial conditions and processes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMNS11B0636T
- Keywords:
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- 0702 Permafrost;
- CRYOSPHERE;
- 0738 Ice;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0794 Instruments and techniques;
- CRYOSPHERE