The Design of Radar Corner Reflectors for the Australian Geophysical Observing System: a single design suitable for InSAR deformation monitoring and SAR calibration at multiple microwave frequency bands.

Abstract

As part of the AuScope Australian Geophysical Observing System initiative, Geoscience Australia constructed a new regional-scale geodetic network that includes an array of radar corner reflectors. The purpose of the new geodetic network is to monitor crustal deformation by combining spatially dense but temporally sparse deformation maps derived from the Interferometric Synthetic Aperture Radar (InSAR) technique and temporally dense but spatially sparse point measurements from Global Navigation Satellite System (GNSS) networks. The radar corner reflector array is also designed to support calibration and validation of Synthetic Aperture Radar (SAR) products from orbiting satellites. This GA Record outlines the prototyping exercises undertaken to determine the most appropriate design of radar corner reflector that can exploit SAR acquisitions at X-, C- and L-band radar frequencies. A set of 18 corner reflector prototypes were manufactured that had different sizes and plate finishes. These prototypes had their radar signatures characterised in experiments conducted at the Defence Science and Technology Organisation ground radar reflection range in St Kilda, South Australia. Following this, the prototypes were temporarily deployed between December 2013 and May 2014 at a grazing property in Gunning, New South Wales. During this deployment the radar response of the corner reflectors was tested in SAR images from the TerraSAR-X, COSMO-SkyMed, RADARSAT-2 and RISAT-1 satellites. As a result of these experiments, a triangular trihedral corner reflector design with an inner leg dimension of 1.5 metres and powder-coated plate finish was chosen for permanent deployment in the new array. Fifteen of the prototypes and 25 new 1.5 metre corner reflectors were fully installed in the new array in the northern Surat Basin, Queensland, by 21 November 2014.