You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
21 December 1994Time-frequency distributions for SAR Doppler rate estimation
The estimation of the best focusing parameters directly from the data is of particular interest in the processing of SAR imagery whenever accurate orbit and attitude information is not available for the satellite-borne sensor. The basic problem is to determine the doppler rate of chirp signals. Time-frequency distributions have been proposed for such application and they prove accurate enough when echoes from strong point scatterers, present within the images area, are used. However, when natural reflectors instead of artificially deployed corner reflectors are used, results are no longer reliable, usually because of the multiplicity of apparently single scatterers. In these cases simple methods will not work, as their outcomes vary too much because of border effects. Hough transform performs well, but it is computationally heavy if accurate estimates are needed. Here the slope of the principal axis of the time-frequency distribution is used to estimate chirp rate. An iterative procedure is used to limit the influence on the accuracy of the results of border effects, background noise and contributions from smaller scatterers at the same slant range. Results are good. A few percent error in the estimated chirp rates has been observed with ERS-1 data.
The alert did not successfully save. Please try again later.
C. Cafforio, Cataldo Guaragnella, "Time-frequency distributions for SAR Doppler rate estimation," Proc. SPIE 2316, SAR Data Processing for Remote Sensing, (21 December 1994); https://doi.org/10.1117/12.197541