Title of Presentation: Technology Development of a Novel Ka-band Digitally-Beamformed Interferometric Radar With Application to Ice Topography Mapping.

Primary (Corresponding) Author: Delwyn Moller

Organization of Primary Author: NASA Jet Propulsion Laboratory

Co-Authors: Brandon Heavey, Richard Hodges, Sembiam Rengarajan, Eric Rignot, Francois Rogez, Gregory Sadowy, Marc Simard, Mark Zawadzki

Abstract: This paper discusses the innovative concept and technology development of a Ka-band (35 GHz) radar for mapping the surface topography of glaciers and ice sheets. Dubbed the “Glacier and Land Ice Surface Topography Interferometer” (GLISTIN) the system is a single-pass, single platform interferometric synthetic aperture radar (InSAR) with an 8mm wavelength, which minimizes snow penetration yet remains relatively impervious to atmospheric attenuation. Such a system has the potential for delivering topographic maps at high spatial resolution, high vertical accuracy, independent of cloud cover, with a subseasonal update and would greatly enhance current observational and modeling capabilities of ice mass-balance and glacial retreat.

To enable such measurements, a digitally beamformed antenna array is utilized to provide a wide measurement swath at a technologically feasible transmit power. To prove this concept and advance the technology readiness of this design we are currently funded by the NASA ESTO Instrument Incubator Program to build and test a 1m x 1m digitally-beamformed Ka-band waveguide slot antenna with integrated digital receivers. This antenna provides 16 simultaneous receive beams, effectively broadening the swath without reducing receive antenna gain. The design and fabrication of such a large aperture at Ka-band presents many challenges, particularly achieving the phase stability required for digital beamforming and interferometric measurements. In this paper we will overview the system concept, requirements, status of the technology development and the experimental scenario by which the beamforming and interferometric performance will be demonstrated.