Characterisation of Corner Reflectors for the Australian Geophysical Observing System to Support SAR Calibration
Thankappan, Medhavy¹; Garthwaite, Matthew C.¹; Williams, Mark L.²; Hislop, Andrew¹; Nancarrow, Shane¹; Dawson, John^1
1Geoscience Australia, AUSTRALIA; ²Horizon Geoscience Consulting, AUSTRALIA

The Australian Government has invested $23 million in building the Australian Geophysical Observing System (AGOS). AGOS will enable highly accurate spatial and temporal estimation of large-scale surface deformation. The key geospatial components of AGOS include Global Navigation Satellite System (GNSS) instrumentation, high precision GPS monuments, corner reflectors and a Synthetic Aperture Radar (SAR) data repository.

The corner reflector (CR) array that forms a key piece of AGOS infrastructure will enable the precise measurement of crustal deformation using Interferometric SAR (InSAR) techniques. The CR array will also provide a reliable means to perform independent and ongoing radiometric, geometric and impulse response measurements for the calibration of a number of satellite-borne SAR instruments. A combination of plate sizes and materials have been used in the design and construction of 18 different CR prototypes. Radar Cross Section (RCS) measurements for all CR prototypes will be undertaken at the Defence Science and Technology Organisation (DSTO) radar signature test facility to compare theoretical versus actual values for a range of azimuth and elevation combinations and characterise the design performance. The prototypes will be deployed at a site in Canberra for testing over a six-month period. Data captures over the test site will be planned, with satellite-borne X and C band SAR instruments to assess the response performance of the CR prototypes for calibration activities.

The progress of CR prototyping including the details of design, construction, RCS measurements, deployment and field performance will be covered in this paper.