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Establishing a Corner Reflector Network for PSI

Jon Leighton(1), Andrew Sowter(1), Doug Tragheim(2), Richard Bingley(1) and Norman Teferle(1)

(1) University of Nottingham, University Park, Nottingham NG7 2RD, United Kingdom
(2) British Geological Survey, Kingsley Dunham Centre, Nottingham NG12 5GG, United Kingdom

Abstract

Persistent Scatterer Interferometric SAR (PSI) has produced measurements of relative land deformation to millimetric precision. However, it can be difficult to confidently validate the results or calibrate any measurements of absolute deformation or 3-d location without relating the data to traditional ground surveying methods, such as GPS or levelling. One method is to place a number of precisely surveyed trihedral corner reflectors in the field. These can be clearly seen in a SAR image and, if permanently and appropriately located, may additionally be used as a stable phase reference for a PSI analysis. This paper discusses the optimisation of a reflector network with respect to a number of factors such as the relationship between the GPS antenna and reflector, the relative geometry of the reflector network, establishing the reflector alignment in azimuth and elevation, site selection, site stability and how the reflectors are secured at the site. This paper also discusses the various issues from a surveying perspective encountered during the planning and establishment of a real network of 12 corner reflectors around the Nottinghamshire area, optimised for ENVISAT acquisitions. Radar observations before and after reflector installation are compared and recent work involving the positional error between radar and GPS observations is discussed.

 

Workshop presentation

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry