Title :
A new method for Doppler centroid estimation for spaceborne SAR based on chirp scaling algorithm
Author :
Zhang, Yunhua ; Zhai, Wenshuai
Author_Institution :
CAS, Beijing
Abstract :
We introduce a new method to estimate the Doppler centroid accurately based on chirp scaling algorithm after investigating the performances of curvature factor Cs and the effective FM rate Ks regarding to Doppler ambiguity number (DAN) and finding that Cs and Ks will lose their functions if a wrong DAN is used and the generated image definition will be degraded. So relations between definition evaluation functions (such as entropy and variance) and the DAN can be used to find the correct DAN which makes the entropy minimum or the variance maximum. Radarsat raw data is used to test the proposed method and find that the performance of using variance is better than that of using entropy.
Keywords :
Doppler measurement; chirp modulation; geophysical signal processing; radar signal processing; remote sensing by radar; synthetic aperture radar; Doppler ambiguity number; Doppler centroid estimation; Radarsat data; chirp scaling algorithm; curvature factor; definition evaluation function; effective FM rate; generated image definition degradation; spaceborne SAR; Azimuth; Chirp; Degradation; Entropy; Reflectivity; Satellites; Signal processing algorithms; Spaceborne radar; Synthetic aperture radar; Testing; Chirp Scaling Algorithm; Doppler centroid; Image entropy; Image variance; Synthetic Aperture Radar (SAR);
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International
Conference_Location :
Barcelona
Print_ISBN :
978-1-4244-1211-2
Electronic_ISBN :
978-1-4244-1212-9
DOI :
10.1109/IGARSS.2007.4422851
