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A Study on Rational Function Model Generation for TerraSAR-X Imagery
Department of Surveying and Geomatics Engineering, University of Tehran, Tehran 14395-515, Iran
Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam 14473, Germany
* Author to whom correspondence should be addressed.
Received: 19 July 2013; in revised form: 16 August 2013 / Accepted: 17 August 2013 / Published: 9 September 2013
Abstract: The Rational Function Model (RFM) has been widely used as an alternative to rigorous sensor models of high-resolution optical imagery in photogrammetry and remote sensing geometric processing. However, not much work has been done to evaluate the applicability of the RF model for Synthetic Aperture Radar (SAR) image processing. This paper investigates how to generate a Rational Polynomial Coefficient (RPC) for high-resolution TerraSAR-X imagery using an independent approach. The experimental results demonstrate that the RFM obtained using the independent approach fits the Range-Doppler physical sensor model with an accuracy of greater than 10−3 pixel. Because independent RPCs indicate absolute errors in geolocation, two methods can be used to improve the geometric accuracy of the RFM. In the first method, Ground Control Points (GCPs) are used to update SAR sensor orientation parameters, and the RPCs are calculated using the updated parameters. Our experiment demonstrates that by using three control points in the corners of the image, an accuracy of 0.69 pixels in range and 0.88 pixels in the azimuth direction is achieved. For the second method, we tested the use of an affine model for refining RPCs. In this case, by applying four GCPs in the corners of the image, the accuracy reached 0.75 pixels in range and 0.82 pixels in the azimuth direction.
Keywords: Rational Function Model; Range-Doppler model; SAR sensor orientation parameters; affine model
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Eftekhari, A.; Saadatseresht, M.; Motagh, M. A Study on Rational Function Model Generation for TerraSAR-X Imagery. Sensors 2013, 13, 12030-12043.
Eftekhari A, Saadatseresht M, Motagh M. A Study on Rational Function Model Generation for TerraSAR-X Imagery. Sensors. 2013; 13(9):12030-12043.
Eftekhari, Akram; Saadatseresht, Mohammad; Motagh, Mahdi. 2013. "A Study on Rational Function Model Generation for TerraSAR-X Imagery." Sensors 13, no. 9: 12030-12043.