Tuesday 23 August 2005

G5

PT0061
A new approach of determining radar interferometry limits and its implication in surface deformation detection studies
Baran, Ireneusz¹, Stewart, Mike¹,
1 The Western Australian Centre For Geodesy, Perth, Western Australia
Author email: I.Baran@curtin.edu.au
Deformation detection using Synthetic Aperture Radar interferometry (InSAR) can be performed due to the fact that surface motion, caused by natural or human activities, generates a local phase shift with respect to the stable part of the imaging scene. However, not all deformations can be detected using radar interferometry. Massonnet and Feigl (Rev. of Geoph., 1998) define the maximum detectable deformation gradient as the dimensionless ratio of half the wavelength to the interferogram pixel size. Even this may be impossible to detect, as radar interferometry suffers from noise in the interferogram phase measurement, which is caused by decorrelation effects and biases owing to satellite orbit errors, atmospheric heterogeneity and filtering. This paper extends the old definition of maximum maximum detectable deformation gradient and introduces a new definition of minimum detectable deformation gradient that will account for the noise factor. The proposed model is developed based on a new methodology that integrates both real and simulated data. Sets of representative surface deformation models are simulated and the associated phase from these models is introduced into real SAR image over several different locations, which are characterized by different levels of noise. A number of cases of surface deformations with varying magnitudes and spatial extent are simulated. Subsequently, interferograms are derived and surface deformation estimated. In each case, the resultant surface deformation is compared with the 'true' surface deformation as defined by the deformation model. Based on these comparisons, a set of observations that lead to a functional model is established. Finally, the proposed model is validated against external data sets. Although the major limitation of the model are its reliance on visual interpretation of the interferograms, this model can serve as a decision-support tool to determine whether or not to apply satellite radar interferometry to study a given surface deformation.

Return to Poster Presentations