Reference Target Correction Based on Point-Target SAR Simulation

The backscattering from man-made point targets like passive corner reflectors and active transponders is often used as a radiometric calibration standard for synthetic aperture radar (SAR) calibration. As new systems emerge and the demand for more accurate systems increases, it becomes necessary to...

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Bibliographic Details
Published in:IEEE transactions on geoscience and remote sensing 2012-03, Vol.50 (3), p.951-959
Main Authors: Doring, B. J., Looser, P. R., Jirousek, M., Schwerdt, M.
Format: Article
Language:English
Subjects:
Applied geophysics
Bandwidth
Calibration
Earth sciences
Earth, ocean, space
Exact sciences and technology
Frequency dependence
Internal geophysics
measurement standard
Microwave radiometry
numerical simulation
point target
synthetic aperture radar
Transfer functions
Transponders
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Summary:The backscattering from man-made point targets like passive corner reflectors and active transponders is often used as a radiometric calibration standard for synthetic aperture radar (SAR) calibration. As new systems emerge and the demand for more accurate systems increases, it becomes necessary to better understand the effects of real or imperfect targets on the radiometric calibration results. Therefore, a point-target SAR simulator is presented which models the complete external radiometric calibration process. It incorporates a number of target properties like frequency response, transponder internal calibration strategies, noise, and interference signals, and it takes the instrument SAR mode settings into consideration. Thereby, the relevant target backscatter variation as observed in the processed SAR image with respect to an ideal or any other target can be determined. The simulation results are relevant during the design process of a new target as well as during the actual calibration of a SAR system. Based on these point-target simulations, correction coefficients can be stated for each target and SAR mode, therefore decreasing the remaining radiometric point-target uncertainties. The quantitative examples in this paper show that these corrections can influence the absolute radiometric calibration by more than 1 dB.
ISSN:0196-2892
1558-0644
DOI:10.1109/TGRS.2011.2162590